Submitted by brad on Thu, 2004-01-29 11:36.
I recently read it costs about $150,000 to put in traffic lights here in California. That's a heavy duty pole, the lights, the power, the connection to other lights and the vehicle sensors. Seems to me modern technology should be able to make that a lot cheaper. New lights are all LED (the energy savings pay for themselves quickly) but that should also mean smaller safer power lines with special digging under the road. (Wonder if they could do it with light pipes and have no electricity up there.)
However, as it turns out, we want electricity up there. It seems there would be a natural marraige between traffic lights and a wireless data network. Years ago I tried to suggest to Metricom that they buy a traffic light control software package and offer free traffic light computerization to any city.
That's because you could then mount your wireless nodes on the lights. You get everything you want -- you are at the major intersections (by definition, almost) and there is power there. A tiny amount of your bandwidth can control the lights from a computer. You're up reasonably high. Metricom used streetlights for their power and altitude.
And while I am loathe to suggest putting cameras at the intersections, ones watching the cars and not the people don't bother me nearly as much and are already there. These could allow human beings to direct traffic at important intersections during rush hour and unusual traffic flow.
A temporary light with wireless camera and control could also do this for special locations that need traffic control on weekends. Police forces can't afford to send an officer out, even though the time saved by the drivers would be huge, and besides it's risky work. However, remote tele-operators could easily do the job and save lots of time and bad traffic.
Submitted by brad on Wed, 2004-01-28 11:13.
Today, the U.S. Agriculture secretary issued a call that nations not ban beef imports from a country (like the USA) just because a single cow has been found with Mad Cow disease.
In other words, exactly what the USA did to Canadian beef when a single cow was found in Alberta with the disease.
And let's not get started on the Weapons of Mass Destruction question.
Submitted by brad on Tue, 2004-01-27 16:02.
For the second year in a row, I'm having a "Superbowl Commercials" party featuring my Tivo. Since the Tivo lets you watch a program while it's being recorded, you can watch the football at 20x speed and slow down for the commercials, and be finished when the game finishes.
To start and give the Tivo a chance to buffer up some game, we head for the hills in a renunciation of the couch potato for a hike. Then we return for the commercials and party.
Of course these commercials are hugely expensive and thus pretty good, and much more fun to watch with a crowd of cynical friends and perhaps some alcohol.
Have you got a Tivo or similar device? Hold a party of your own. I was asked, tongue-in-cheek, whether skipping the football part was unamerican. What could be more american than watching commercials?
Update: Party was a grand success, big crowd, all had a good time. After 2 years this is already a tradition. Tivo, bless their Orwellian hearts, tracks user clickstreams and reported in their press release that the Janet Jackson nipple was the most replayed event in their history. And yes, the folks at my party also wanted a slo-mo rewind.
Update: A new superbowl commercials party is planned for 2005. This time, it will be in HDTV, using the open source MythTV software. I'll blog a more detailed entry about it after the party.
Submitted by brad on Tue, 2004-01-27 06:49.
I often talk about Challenge Response spam filters because I wrote the first one. One complaint people make is that the filters will challenge even forged mail, causing a challenge to be sent to the forgery victim. While this is not a DOS attack window as some people believe (since you can as easily DOS the target directly as get others to do it for you) it does need more consideration.
However, there are some autoresponders who have no excuse in this, and it is them I am railing on today. With the latest worm program, I am getting "bounces" back from anti-viral mail filters which tell me, "The mail you sent contains a virus and was not delivered."
Of course I didn't send the mail, my address was forged. What bothers me is that the anti-virus program clearly knows there is a virus, and presumably then should know it is the sort of virus which puts in a fake address.
So why it feels the need to send an error to the address it knows is fake, I don't know. The bounces I can tolerate, the bouncing software has no way to know it was a virus, but the anti-virus software has no excuse.
Addon: I'm going to promote a note from the comments because naive me didn't think of it. The virus companies may be happy to send this "your virus was bounced" mail to the wrong address because it's an ad for their anti-virus service.
Submitted by brad on Tue, 2004-01-27 06:33.
I seem to be thinking a lot about the future of automatic cars these days. Already we're seeing cars in Japan that can park themselves in a tight parallel parking spot, and this leads me to think that the next market for the technology, after the basic automatic highway, won't be the city street but the parking lot.
Parking lots eat a lot of space, and where the land is expensive, automatic cars will offer automatic valet parking. Drive to the mall/office/whatever, enter the automatic lane and be whisked to the door. Get out and your car will run off and park itself efficiently, possibly some distance from the building. (In the future with more fully automatic cars trusted on city streets, it might rent itself out as an autotaxi.)
When ready to leave, use your cell phone to tell the car to come to the nearest door, and it will be waiting there. Obviously that's a great convenience, but the real reason this will happen is it saves a bundle for the building/parking lot, because they can park more cars in the same space, or even park cars offsite. Whatever cost is needed to bury guide-wires or other transponders is easily justified by the efficiency gain, especially in downtown multi-story lots, many of which already justify the cost of humans to do the work.
Later, however, I will reveal the big catch that may keep us from this.
Submitted by brad on Mon, 2004-01-26 10:23.
I went around and counted that we seem to have around 30 birick and wall-wart DC power supplies plugged in around the house, and many more that are not plugged in which charge or power various devices. More and more of what we buy is getting to be more efficient and lower power, which is good.
But it's time for standardization in DC power and battery charging. In fact, I would like to move to a world where DC devices don't come with a power supply by default, because you are expected to be able to power them at one of the standard voltage/current settings.
One early experiment is on airplanes. I have an adapter that takes the 12v from the airplane, and has many tips which put out different voltages for different laptops. These are expensive right now, but on the right track.
Our other early venture is USB, which provides up to 500ma at 5 volts. Many small devices now use USB for power if that's all they need. There are devices that plug in to USB only for power, they don't use the data lines. Some come with a small cigarette lighter plug that has a USB socket on it for car use. This includes cellular chargers, lights etc.
I think a good goal would be a standardized data+power bus with a small number of standard plugs. One would be very tiny for small devices and only provide minimal USB-level power, a couple of watts. Another would handle mid-level devices, up to a couple of amps. A third would be large and handle heavy duty devices up to say 20 amps, replacing our wall plugs eventually. There might be a 4th for industrial use.
In full form, the data bus would be used for the components to exchange just what power they want and have. Years ago that would have been ridiculous overkill, today such parts are cheap. However, to make it simple there would be a basic passive system -- perhaps as simple as a finely tuned resistor in place of the data components -- to make it easy and cheap to adapt today's components.
A fully smart component would plug into the smart power and get a small "carrier" voltage designed to run the power electronics only. A protocol would establish what power the supply can provide and what the component wants, and then that power would be provided. read more »
Submitted by brad on Wed, 2004-01-21 14:25.
Another transportion item, because last night the train I was on hit a car stalled on the tracks (the occupant is OK, though was hit by the car when the train bashed it.)
Since trains do hit things, why aren't solutions to this more common in our data network world? A laser detector over the grade crossings would be simple enough.
At dinner, my friend Kurth Reynolds made a suggestion that I have improved. How about a small robot, equipped with camera and other sensors, which travels far enough in front of the train that if it sees a problem on the track, can send a signal back to the train in time to stop it. Trains take a while to stop, which is one of the reasons they can't do anything when they see a car or person ahead on the tracks.
You can't be too far ahead or you enter the "space" of the earlier train on the track, though during any tight conflicts you can of course give up this "foresight" and bear through (or slow down.)
If you have a human driving the train, you can show them video of what's ahead of the robot and give them time for a decision. Some decisions (Robot hits something or derails) would be automatic. Of course the robot might hit the car stalled on the tracks (though it can stop much, much faster than a train) but do far less damage.
The robot would be tall enough to go over the suicides who are "sleeping" on the track, but light enough so a car hit by it would survive.
Simpler for shorter runs like commuter trains would just be cameras along the track beaming to the oncoming trains. The engineer could be seeing a mile ahead at all times. Hey, if x10 can sell 2 broadcasting video cameras for $80 (WARNING: Don't buy from their web site, you will be spammed to death) I bet this can be made affordable.
This is important because some people don't think we should have rail with grade crossings. Without grade crossings, rail becomes vastly more expensive.
Some updates five years later: Some have worried the robot could hit workers or cars. Today, we are more comfortable we can build robots which would use LIDAR and never hit anything that wasn't running onto the track. The robots would also be light and perhaps have airbags to soften the blow against something rushing onto the track. When coming to a grade crossing, the robot would actually stop at the crossing and wait for the guard to come down (for the train, if the path is clear) and continue to monitor the crossing and report if something stops in it. Then it would speed up again and start going down the track to assure it is far enough ahead of the train.
Submitted by brad on Wed, 2004-01-21 05:38.
I'll be writing more in the future on ideas for auto-drive cars (both plus and minus) but let me start by asking the question of why the oil companies haven't jumped up to foot the bill for the development of automatic cars and highways?
It seems a big win for them. Given the availability of a car that would drive itself on the freeway and perhaps a few major roads, people would be much more willing to tolerate longer commutes, and that seems a win if you sell gasoline. A multi-billion dollar win.
Not completely -- the automatic cars will be more fuel efficient (simply driving at constant speed is more fuel efficient, but they will also be more likely to be hybrid designs.) But that's coming anyway. Given the ability to read, work or sleep during the commute would easily make people willing to commute for longer. In fact, for those who can easily sleep, they might welcome a longer commute to get the chance to have a decent sleep period. (Though there are those annoying people who are asleep before the plane starts its taxi. I hate them.)
We're also talking about a car where, while in it, you can have a decent speed internet connection and phone. The commute time effectively could become fully effective work time. Or TV watching time, or reading time.
Of course, in theory an automatic car in special lanes would also not get subject to traffic jams, so a longer commute would take the same time, and a longer commute sells more gas -- though admittedly traffic congestion also sells more gas.
But once again, the upside for oil companies is huge, and it's also high for the automakers, and the highway planners. It's mainly not good for public transit, since it takes away one of its advantages. We already know the basics of how to build an automatic car on an automatic highway. One of the big remaining barriers is money, and this could be the source.
I've added some extra notes below... read more »
Submitted by brad on Mon, 2004-01-19 10:56.
Like many, I am interested in reputation systems, and eBay has built the largest public reputation system. Many have noted how feedback on eBay is overwhelmingly positive — a 97% positive rating would be a reason to be wary of a seller.
It’s also noted that people do this because they are scared of revenge feedback — I give you a negative, you do it back to me. One would think that since the buyer’s only real duty is to send the money that the seller should provide positive feedback immediately upon receipt of that money, but they don’t.
Some fixes have been proposed, including:
- letting you see the count of total auctions the party has been buyer or seller in, so you can see how many resulted in no feedback at all. Right now only eBay knows how large that number is.
- double-blind feedback. That is to say that feedback is not revealed until both parties have entered it, or if only one party enters it, after the feedback period has expired.
- Marking revenge feedback, ie. putting a mark next to negatives that were a response to an outgoing negative.
Thus you could have very low fear of revenge feedback and there would be no argument about who should go first.
This idea’s fairly obvious, so like many other obvious ideas about eBay one wonders if eBay doesn’t feel some benefit to themselves from not doing it, though it’s hard to see. I’m also curious as to why eBay doesn’t offer a “going, going, gone” auction where the auction closes only after 5 minutes with no bidding. That seems to be in the interests of sellers (and eBay which gets a cut of the selling price) and it’s certainly not something they are unaware of.
The only proposition I’ve heard is that eBay has decided that there is a positive value to itself (and possibly sellers) from bid-sniping, the process of bidding preemptively in the last minute of an auction to not give other live bidders (who didn’t use the automatic rebidder) a chance to come in with more. The only way this could be good woudl be if Snipers deliberately overbid in order to trump anything. Any research or thoughts on this? It may also be the case that the sniped auctions are more “fun,” or more of a contest. And finally having fixed closing times does facilitate participating in multiple auctions for the same thing.
I have also posted updated eBay thoughts and an even simpler system which eliminates revenge and in fact now have an eBay tag for all eBay related posts, including thoughts on eBay’s solution to all this.
Please Note: This thread is for discussion of philosophical or abstract aspects of the feedback system. Please do not post stories of your own particular problems from a particular seller or transaction. Keep it abstract.
Submitted by brad on Sat, 2004-01-17 11:55.
Thinking more about the future of mobile audio (see Tivo for Radio Entry) I start to wonder if XM and Sirius satellite radio are doomed propositions. They seem like a good idea, nationwide radio, 100 channels, many commercial-free.
But how many of the stations does any given listener actually use? I would guess most people only listen to a few of them, just as they only listen to a few on the local dial.
And more to the point, how many need to be live? Very few. Certainly not the classical stations or other music stations. Generally only news, sports and (localized) traffic and weather need to be truly live. Political talk shows should be current though need not be live.
So what this means is that the satellite systems may be way overdone for bandwidth. One might attain all one wants from Satellite Radio with the hard disk based car-audio system, which by 802.11 sucks down all the new content it needs when in the driveway (or when near an authorized 802.11 node.) The live content can come from conventional radio, or the sideband on a TV station or other local transmitter.
(The local radio stations might not be willing to assist so readily in their own demise.)
The selection of Internet Radio blows away even satellite radio. Combined with your own personal music collection it's a no-brainer. The quality is just fine for use in a car. XM an Sirius proudly boast they have 3 classical stations, 3 jazz stations, whatever. Internet radio has hundreds of each type of station, as well as custom stations.
One could build an equivalent satellite network buying just a few hundred kilobits of bandwidth (for all the live talk, sports and news stations, which can use higher compression codecs as they are just talk) from satellites if you need the coast to coast coverage on the live data, or piggyback on other platforms if you just need the major areas.
You could also cut deals with 802.11 hotspot owners to let cars driving by quickly pick up more live news and talk. You laugh, but if you are in range of 5 megabits for 10 seconds, that's enough for 40 minutes of 20kbit talk radio.
XM and Sirius need to pay for a hugely expensive satellite infrastructure. Did they overbuild?
Submitted by brad on Fri, 2004-01-16 05:54.
I plan for this to be mostly an essay blog rather than a link blog, but I could not resist this story of yet another nightmare at airport security, as a student is ordered to "dispose" of her pet fish while trying to take it home with her on the plane.
So now the essay. Like many of you, I have read tons of these crazy security stories. Stories of cruelty, stories of pointless security that simply gives the appearance of security without making things safer. Innocent people harassed. Pilots arrested over nailclippers. People groped. People kept off planes for reading the wrong book.
Now, you might be firmly of the mind that we must increase security and make some sacrifices. But if that's the case, there need to be checks and balances on the security decisions.
Right now, when people go overboard on security, there is no negative consequence for them when they get it wrong. They have no reason not to go overboard. We're too afraid that if we discipline them at all, they might let something slide and let Al Qaida on the plane.
But it can't work that way. There needs to be a consequence for going over the top. People should be able to lose jobs, get fined or disciplined. Security workers need to think twice about whether they should do something.
This should particularly be true if it's obvious that what they are doing gives only the appearance of security rather than real security, unless we decide it is our policy that the appearance of security is more important.
(And while I see the argument some might make for that -- that the public has to feel confident that they are safe in transit or they won't travel -- I don't buy it long term at all.)
The men who made the fish policy, or the men who enforced it, should be called to account. If they have a reason for it, they should have it ready for the passenger. If they don't, somebody should be disciplined.
No, I'm not saying don't give them any discretion or let them make any mistakes. But the mistakes should be noted, explained, and if repeated, punished.
Submitted by brad on Thu, 2004-01-15 14:19.
We're not there yet, but let me write my notes about what future digital cameras might do to help us organize our huge collections of photos: read more »
- GPS and compass in the camera knows where it is, and where it was pointing. Thus, if standing on the south rim of Grand Canyon and pointing north, probably a picture of the Grand Canyon. Organize your photos on a map.
- Record audio said while taking photo if special button pressed. Later, upload audio to PC where it's able to do speaker-dependent speech to text at its leisure to caption the photos.
- Face recognition. No, I'm not kidding. While this is Big Brother technology, and not very useful in airports, one thing it can do is try to find similar faces. So once you tag your mother, it will be able to search your photo collection for other shots with your mother. This is much easier than trying to take a random person and see if they are on the FBI wanted list.
Submitted by brad on Tue, 2004-01-13 09:39.
The USA and Canada have agreed to tell each other before deporting citizens to third countries.
In theory, that's to not repeat the horrific story of Maher Arar, the Canadian programmer, born in Syria, who, while changing planes in New York on a flight from Europe to Montreal, was grabbed by U.S. agents, grilled and then deported to Syria, allegedly so the Syrians could torture him in ways the U.S. could not.
Arar wasn't even trying to get into the USA. He had been investigated on some fairly weak connections and cleared, but his name got on the lists. The Syrians tortured him for suspicion of membership in a Muslim organization opposed (like the USA is opposed) to the Syrian regime while he was a teenager in Syria.
Instead of being deported to Canada, his nation of citizenship, he went to Syria.
This is a particularly nasty story which you should know about if you are a U.S. citizen. Arar was cleared, but the hard truth is the USA shouldn't be setting even the guilty up for torture, let alone the innocent.
Submitted by brad on Mon, 2004-01-12 11:14.
Recently, we picked up a Rio Karma, which is a 20gb handheld jukebox that plays MP3, WMA and Ogg Vorbis. Particularly nice things about it include the Ogg support and the fact it has Ethernet, so that any machine on our net can transfer music into it. That's about all it does with the ethernet (it also has a small web server to serve the manual and a java transfer app) but I expect it will do more later, like be a streaming media gateway when docked on the stereo, allowing control from anywhere.
We've also used it a lot in the car, where we get to use it a bit like a Tivo for Radio. The Tivo is the hard disk video recorder I have for TV, and is the only way I watch TV now. Every Tivo owner has probably wished they could pause their radio as well.
To start, I download radio shows with some simple linux scripts. Some programs like NPR's "On the Media" and the CBC's Quirks and Quarks let you download shows directly. Kudos and Huzzah to them.
For other shows, you must capture streams and listen later, which is legal. For example, each morning I capture a 32kbit MP3 stream of 2 hours of "Morning Edition." It syncs to the player, and can then be played during the commute. The newscasts are 2 hours old but you can fast-forward, pause and rewind, which is great. read more »
Submitted by brad on Fri, 2004-01-09 10:17.
For some time I have been musing over the design of an ideal home A/V system using digital technology. Sadly it's not coming, in part because it's illegal under the new Broadcast Flag rules.
To read my design of this system, and the musings of the legality of it and why that presents a problem, see a draft on an Ideal A/V digital system
Submitted by brad on Thu, 2004-01-08 06:42.
Just about every blog has pointed to Moveon.org's Bush in 30 Seconds contest for anti-Bush TV spots.
The candidate spots are witty and clever, but I think they miss the mark. For those who have already decided they will vote for anyone-but-Bush, they bring many cries of approval. But that's not who they have to convince.
They need to win the undecided voters, as well as a particular segment of the confirmed Republican block. You won't do that in 30 seconds, of course, but you might somebody on the path to looking at more issues.
A few of them are on-target, such as In My Country and Army of One. But the best of them, Child's Pay, seems way-off this target to me.
Of course, I'm not a US Citizen so I don't get to vote. If I could, neither the Republicans or Democrats seem likely to inspire me. But I do feel that due to civil rights concerns and the horrible damage being done to the reputation of the USA in the world, President Bush has to go.
As to the civil rights concerns -- there is a fairly strong contingent in the Republican zone that are big supporters of personal privacy and the 4th amendment. They're very scared of what's happening with the Patriot Acts and the actions of John Ascroft. They will turn on the President if they see more of this, some of them at least.
Submitted by brad on Tue, 2004-01-06 04:49.
Transit idea #2. Air travel is getting to be like hell, with searches and the need to get there so far in advance of the flight to be sure you will get through security that it cancels much of the benefit, turning 40 minute flights into 3 hour ordeals. High Speed train advocates point out the downtown-to-downtime time of the train on routes of 300-500km beats or is competitive with the plane, and it's true.
But this would not be true if they could check you in and through security while on the train, bus or ferry to the airport, and then said bonded carrier took the cleared passengers directly to their gates in the cleared section.
Imagine you board the special airport train downtown. Security personel and airline agents move through the car on the trip with wireless terminals, metal detector wands and an X-ray machine. Their machine moves down the aisle (a bit easier in a ferry than a bus I will admit, but it could be designed) and everybody behind them is cleared, everybody ahead of them waiting, until they get to the end, and the whole train/bus/ferry is cleared. Then, if not on a bus, you are dropped where you can transfer to special busses which drive around the inside of the terminals on that little road, dropping you at stops near your gate in the cleared area. Your checked bags were stuffed at the back of your train and are put on the right conveyers.
This was easier to work out before 9/11 but I still think it could be done. And many passengers would happily pay a fair bit extra for this, because the result -- by making use of the otherwise dead time heading to the airport -- would be to have a zero-time trip through check-in and security.
You could even insist on web pre-checkin to smooth the process. Even people who lived closer to the airport than downtown might find it worth the time to get this train.
The handicapped would need a way to get from ground level to the jetway
entry level. Probably require airport staff to escort them to elevators in such airports. Or they would (if the ADA allows this) be forced to use the existing system. Does the ADA forbid improvements for those who can climb stairs and keeping the status quo for those who can't?
It would also reduce congestion at the airport and the existing security stations and free up parking and reduce private car exhaust. A win all round, worthy of the cost of any extra security staff or machines.
Those without checked luggage could schedule to arrive at the gate 15 minutes before take-off the way we used to be able to do on short flights, if using a ferry or train with dedicated right of way. With checked luggage you would need to go earlier to give them time to rape that.
This kills the argument in California that a high speed train from SF to LA would be worthwhile compared to the current downtown to downtown time. You would get the best downtown to downtown time by putting in such rail just from the downtowns (and other places) to the airport, and using the time on the train to advantage.
Update: I have expanded on the idea on this page on transit checkin
Submitted by brad on Mon, 2004-01-05 07:47.
I'm going to write more in the future about how transportation is not making using technology. Let me start with streetcars and the bus.
People use transit a lot more if it is able to beat the car, or at least keep pace with it. Thus we spend a lot of money on dedicated right-of-way for subways, trains and streetcars.
But this is really inefficient. The dedicated right-of-way sits empty 95% of the time. It does nothing so that a train can pass over it every 10 minutes (or more.)
Imagine a system where street cars and electric bus lines run on regular city streets. But it's illegal to drive in front of the car or bus in its special lane. It's OK to drive behind it, but if the car or bus ever has to hit the brakes because you're in front of it, it snaps a picture of the plate, and your car is sent a ticket for $200 for blocking the lane.
The main downside I see to this is the risk of people pulling dangerous stunts to get out of the lane, trying to merge into heavy traffic in the next lane to avoid the fact ticket when they see a bus coming up behind them. The system would have to be tweaked and tested to avoid that, with bigger tickets for making an unsafe lane change etc.
Large carpools (4 or more) might also be allowed in the lane, private busses, shared taxis and so on. Of course, once the streetcar went past, people would zoom behind it to follow its speedy course. But that's good. It's far more efficient than dedicated right-of-way, but gets near the speed.
Traffic signals would of course have to be coordinated with this, stops somewhat limited and there would probably remain some dedicated right-of-way in certain areas. We won't tear out our subways to make this happen.
Submitted by brad on Sat, 2004-01-03 11:47.
There is much talk of Location Based Services and geographical annotation these days. We either see scary LBS (network tracks you all the time, sends you Latte coupon when you walk near Starbucks) or query based services -- "based on where I am, where's the nearest good place to eat?" That's something Vindigo does without nearing a GPS, and does it fairly well.
I've been wondering about proactive location based services and annotations that work for you and protect your privacy.
One I envision works like this. Imagine your cell phone or other portable location-aware device has a big yellow button. The button, if you press it, means "The service here sucks." Not the cellular service, but the service (or quality, or prices) in the store you're currently in. Pushing the button sends your opinion to a reputation database associated with the location.
Stores will fear the button. If you hold it up and threaten to push it, they will probably snap to attention. Why? Because you and many others will also download the database into your location aware device. If you walk into a store with a high rate of complaints, your phone will ring and warn you about where you're going.
It would probably try to electrocute you if you walked into Fry's electronics.
There are many valuable servcies when you know you're looking for geographical information, but many others that can warn you of things you didn't know to ask for. That you're walking into a bad part of town or driving into bad traffic. That you're near a historical site that's of interest to you, or a store that sells something you've been looking for.
As noted, all this can happen by pre-downling the data into a device that has the GPS-WAAS or other position information. Your device looks out for your interests based on your location, which it doesn't have to transmit to anybody. Even your vote with the yellow button can be transmitted up later, so you're not tracked in real time.
Submitted by brad on Wed, 2003-12-31 07:25.
There's a growing and dangerous movement to try to stop spam by forcing all mail senders to provide ID with each mail they send. Signing mail is not a bad idea, in fact it's quite useful, but to stop spam you have to make everybody sign their mail.
In the past this was a non-starter because this means forcing everybody who mails you to get new mail sending software, or at least to have their ISP do this. But spam has made us so angry people are talking about doing this, even though we don't demand ID for paper mail that, in theory, can contain white powder that can kill you.
This would mean the end to anonymous mail and a lot more complexity in our mail systems. So I sat down and said, if you are ready to force people to get new software, could you stop spam with something more distributed and still allow anonymous mail.
Indeed you could, and I have a proposal outlined to combine CPU stamps, challenge/response and signature to end spam