Guild's in Ryzom work in much the same way as per other MMORPG's. The usual suspects of the one leader, some officer's and then members fill the ranks. Unlike alot of online games though, Ryzom allows guilds the use of guild housing to meet / greet and socialise; not a feat many companies can say they have achieved.
Below are some of the more popular guilds in operation throughout Atys :-