So many web services do this wrong, that it isn't even worth doing it right: no one is going to complain that your service doesn't accept their "wacky! quoted"@

So many web services do this wrong, that it isn't even worth doing it right: no one is going to complain that your service doesn't accept their "wacky! quoted"@email.address Sometimes, you aren't validating a whole string, you are searching for email addresses in a sea of text, or an arbitrarily delimited, user-entered list of contacts. Support usernames with alphanumerics, dashes, underscores, periods, and plus signs; Require a single @; Support domains with alphanumerics, dashes, and at least one period. Screw anyone with something more complex than that. Done deal.