I think email is still somewhat necessary.  First of all,  you aren't everyone, just because email isn't useful for you doesn't mean it's not useful for your users.  Second of all, most web apps require an email address to sign up, if for no other reason than to send a forgotten password reset.  So even all those kids who really don't have a use for email still have an email address to sign up for things like Facebook.  Speaking of Facebook, this service and others have a lot of resources to research these sorts of things, and they still use email as a signup.<p>As a user, I prefer when a service uses email for usernames.  One reason is that I can remember my email address, even if I don't use it.  Often I forget the usernames that I use to sign up for various services.  The other reason is that I know my email address is going to be unique, so that saves me from playing the "username is already taken" game.<p>I don't really have a problem with spam or known email users who are over active.  Gmail does a pretty damn good job of filtering the spam.  Custom filters do a good job of clearing things that aren't really spam but still annoying.