So does sending the verification email, so it's a wash. Thinking about implementing email validation + verification is a great opportunity for developers to do two things:

1) Consider if you really even need to verify that email address. Why are you collecting email in the first place, why do you need it? HN is a great example of this - email totally optional, if you forget your password it's on you. Lot of online services going in the wrong direction with requiring a phone number.

2) Trust the user. Okay to give them nice nudges ("you probably meant gmail.com and not gmail.co") but if I really did mean gmail.co, let me through if I insist.

Don't throw up a garbled mess of a Regex[0] that only serves to frustrate me when I try to sign up with my vanity email. I'll abandon the sign-up entirely.

[0]: https://stackoverflow.com/questions/20771794/mailrfc822addre...