New factions don't need separate forums. discoverygc.com is more than enough. For example, SMP used to have a separate forum. The only guys posting there were the leader and the second in command. Using disco forum shows a level of activity, the quality of RP and it's used by almost everyone. Hell, even the CR forum is inactive since we moved all the reports and communications on disco.
But, if you really, really want to make a forum, try zetaboards.com