What are the pros and cons of using an email address as a user id?

Question

I\'m creating a web app that requires registration/authentication, and I\'m considering using an email address as the sole user id. Here are what I see as the pros and cons (upd

Answer 1

One con might be that if it's an email address the login can be guessed by people and brute force attacks attempted. Which is not really a big issue, since on most sites today the logins are publicly displayed.

The biggest pro is that logins are easier to remember this way.