Yeah, you can change your username, and there is a setting that only admins can change which also changes your username. But, they don’t do it because it does destroy tags, and I think that you can change your username the first three days because you probably haven’t get tagged so much that the tags and the forum might get laggy.
This is an official post by one of the Discource developers (@codinghorror) on the Discource forum:
It says this:
Then you can set the site setting value to whatever you want, right now it defaults to a 3 day window after signup. Set it to 999999 if you like.
Note that all @username references to that user in post text will be broken after the name change.
So, the tags will not work if you change the username, but you are right, the admins (like @Liza for example), need to change a setting called “username_change_period” or access another kind of setting. I think that they don’t do it because it will break a lot of tags, and it might be like titles as well, they might not want everyone to change their username, but I agree, it is cool, and if you want to do it, I hope that it can be done. You could e-mail THT about it.