I get many errors because people (mostly younger people that probably don't use email regularly) type in incorrect email addresses (leave out the '@', use : instead of . and so on).
While I've heard of this trend, I find it quite surprising.
Registration for almost any website/app/service needs a valid email address. And. although IM/Twitter/FB take care of informal communication [can you get a Twitter account without email?], there are plenty of cases where email still works better than the alternatives. How old are these younger people?