We now allow you to change your BGA username, and/or to take over the username from an inactive account.
We hadn't implemented this feature before, because it was difficult to realize technically. But for some cases we found out that it was useful to provide a - limited - feature to change your username, so we changed our mind on this.
Each account on BGA is now allowed to change its username ONCE (from Preferences / Account). It is really only possible ONCE, so do it carefully.
In addition, if you ever wanted to have a specific username but couldn't because it was taken by an inactive account created years ago, you can now get it by using this feature (except if the current owner refuses to release it, of course).