It is advisable to keep your username here the same as on the SA forums but is not required. Eventually avatars will be implemented.
*Note* Currently all registrations are manually approved. Post in one of the Dominions SA threads to verify goondom, and include a link to your Desura profile to show you bought the game. If that doesn't work for you, we can figure something out. Hit us up on #dom4goons on synirc.