> You don't usually want to give out your email address as a form of general ID, But why is that? Is it because people will abuse it and send you data you don'

> You don't usually want to give out your email address as a form of general ID, But why is that? Is it because people will abuse it and send you data you don't want (spam)? The same problem applies to twitter ids, except that not many people are spamming yet (I assume). I guess there's also a single-point to detect spammers, which might make detection easier, but I'd be surprised if that was enough to control the problem.