On the point of clans, a few questions: How do you join clans? I read up on how to make one, but do you have to be invited to join one? Also, what's the benefit of being in one besides private forums?
Yes, you have to be invited. You probably have to mail whoever they say on the clan page.
https://www.warzone.com/Clans/?ID=141I mean you get an icon next to your name :P But there are no direct benefits, apart from clan members to play with and playing in Clan League etc. Oh and a forum as you said.
For diplo/rp games, it's good to join a clan, to avoid boot's rage-quits etc. Not sure what diplo clan is hip atm thu.