Requiring users to change their login names is a thorny issue. When Yahoo told Marc Hedlund that he’d have to change his login hame, he decided to cancel his Yahoo account instead. I got burnt by this when AOL merged their AIM and Netscape portal namespaces. They forced me to change my login name in spite of the fact that I had registered rafeco in both places. Rather than let me merge my accounts, they dumped them both and required me to come up with a new login ID. That’s just bad. (I haven’t really used AIM or Netscape’s portal since.)