Why do people put angle brackets around <urls>
Quite frequently in non-HTML documents, such as E-mails, people will enclose their URLs in angle brackets, such as <http://foo.com> What is the origin of this? For me, it just makes cutting and pasting the URLs much harder (it's easier if they have whitespace around them and easiest if they are on a line by themselves.) It's not any kind of valid XML or HTML in fact it would cause a problem in any document of that sort.
There's lot of software out there that parses URLs out of text documents of course, but they all seem to do fine with whitespace and other punctuation. They handle the angle bracket notation, but don't need it. Is there any software out there that needs it? If not, why do so many people use this form?