I cleaned it up.
Originally I bought over the account info of all the cubits.org members. Once that was done and everyone who was interested came over, logged in, and posted here at ATP, it was time to do some cleanup.
So, I went through and every account that has never posted to ATP (either since the launch or in any of the thousands of posts that were moved here from Cubits) and never logged in had the usernames removed.
Anyone who has an account at Cubits but not ATP can easily fix that by clicking the "Join now" link.