I was not able to register because I never received the verification email. The reason it failed is apparently that comcast, the owners of the comcast.net domain, and the largest ISP in the US, have decided that you guys (or your domain) must be spammers, and they filter out the email before I can receive it. I have no control over that. You can try to persuade them otherwise.
There is no provision to get around such a problem. In particular, if I claim I never got the verification email, I should be offered the opportunity to register with a different email address. Hell, that could happen if I made a typo in my email address, for that matter! But no, if I try to register again, even with a different user name, you disallow it. I had to be clever, and register with a different browser, a different username, and a different email address.