Stop Validating Email Addresses with Regex (2012)
Can't upvote this enough.<p>There simply is no need to check the email addr provided by the user. Send the mail, if it bounces, the user has only himself to blame. What if I don't want them to go through the hassle of an activation link? Then I don't bother with an email account in the sign-up process in the first place. If they want a passwd reset method, they can later provide an email in their settings page, if that isn't valid, well, tough luck.