Although the forums would be separated, the attitudes wouldn't. I agree with almond on this. By introducing forums for guilds all of that glory of being in one would go straight to some power-hungry heads. Your leaders would eventually hate one another and guild members would become so devout to their stance that they wouldn't want to participate in individual RPs with members that aren't associated with their guild.

Here we encounter one of Gaia's many problems. One of the reason that many of their members don't get along as easily as we do is because of the factions that are formed. Factions become dangerous over the interwebz just as they become dangerous in the real world.

Don't get me wrong, I think guilds are cool; but only if they are able to be controlled. We won't mind if you start up a small guild for fun and invite a few members here and there, but as almond said, "It doesn't warrant a forum."