I'm not saying that having a GitHub account should be a _requirement_ for joining, but it could be a part of the "business logic" for new account validation. It's very easy to implement. If you're an established Nim developer, the forum rolls out a red carpet. If you're not, your first X posts are hidden until a moderator validates them. Or something like that.
Linking forum profiles to GitHub is a good idea for a number of other reasons as well: keeping track of who is who, who wrote what, etc.
