Invade: It ends up being complicated as hell if you don't plan ahead. I did this back in October 2007 with four separate clans and we really didn't do anything until December because everyone was like "WTF?" So my advice to you is if you decide to merge, contact Clan Forum Moderators ahead of time so they know to remove the separate clan forums of the merging clans and make one for all of the mergers. Also make sure all your members know what's happening and tell them when it's happening, too, so they don't scroll down the day after a merge and find that their old forums are suddenly missing.