[ShannonAlther]

Why would you allow users to change their display name? It's a forum, not social media.

[always_good]

Of course it's social media. The username and avatar is one's social identity on a forum. I think you have a very narrow experience with forums if you find it surprising that someone wants to change their username if you accept that they would also want to change their avatar.

[foxhop]

Checkout Remarkbox, I generate them a random display name when they sign up and then allow them to change their display name later.

Regardless of the type of application, why would you not want a user to be able to change their display name?

If I was able to change my display name on hacker news, I think I would.