[rtp]

A better way is to check that the email the user entered matches a typical email format, and if the email doesn't match, then warn the user that he/she might've entered the wrong email address (for example writing foobar@gmail, or [e-mail].).

[Wicher]

I think [e-mail]. should actually work. IIRC, that last dot is the root of the DNS hierarchy.

Try http://news.ycombinator.com./ ;-)