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I think any tropes about aliases or codenames would apply to usernames too
Of course, but I think the fact everyone is given one is significant and that it's such a Z-gen thing to do. Also, the fact that the characters are not called like that in normal dialogue, not even in the group chat conversations; it's just a gimmick in their usernames that flavors the chatroom, so to speak.
Here there be cats.
I've noticed in several chat fics that the characters will assign themselves or each other nicknames indicative of their appearance or personality as their group chat usernames. Sometimes is simple stuff like 'Kit Kat' while others it's entire phrases 'I Swear It's Red Paint'.
Do we have a trope for this?