At first I didn't agree with you, but now that I read it again, I do. I don't think the domain name should be disallowed, just the addition of their extension. So for Google.com, it should just be Google. This won't change though, but thought I'd share my views.
eXploit Reviewed by eXploit on . disallowing domains on nicknames ? well i've seen few people just to promote their websites they are using domains on their nicknames such as "chris.com, fileserve.com, google.com" and its kinda annoying. it should be disallowed !! only nicknames should be allowed without domains! Rating: 5