Why is the user assigned the username with 0 at the end.

[Adam C]

As an instance, a new user has recently registered at the online swim community with the username "swimatlanta 0". I have not observed any other users with the name "swimatlanta". Do you think the reason for the "0" at the end is that we have a group named "swimatlanta"?

[baris]

Yes, since groups and usernames can be mentioned with @<slug> it prevents duplicates in groupnames/usernames