Brad:

You're making the mistaken assumption that anyone who vlogs is doing it because they want to reach a wide audience.

I agree that 95% of vlogs aren't worth watching, but let's face it, 95% of text blogs aren't worth reading either.

But if someone enjoys the process of producing video, why discourage them from posting it online? Some fraction will turn out to have talent and produce worthwhile material. The rest....nobody's forcing you to watch. No harm, no foul.

Now, if instead of saying "Please don't vlog," you'd said, "Please don't expect a lot of people to watch your vlog," that would be a statement I could agree with.