Welcome back! Feel free to reach out to me whenever you are looking for something to do and i'll tag along if possible. My icq is 93303733.
As for active guilds and/or alliances. There are are three off the top of my head (and people from these feel free to correct me for any mistakes) that i know are active:
1) PAS - As far as i know this is the largest guild on the shard. They are very active and have an event/activity almost every night. You can find their website here:
People's Army of Sonoma :: Index - People's Army of Sonoma . Full disclosure: i have a few chars in this guild. Good people.
2) TI / r^us / TLF - I believe all these guilds are in a single alliance and i KNOW i am missing a few. Very nice people, with the first two guilds being tamer-oriented (but not exclusive to tamers afaik). TLF is Queen Mum's guild and she is probably Sonoma's most well known person and is very knowledgeable/helpful. I believe TLF is just her family, but if you see her she is a great resource for knowing Sonoma's inhabitants. Full disclosure: I have a few chars in TI. Good people.
3) WAKA - A PvP guild that operates on multiple shards, but i believe Sonoma is "home" to them. I am not a PvPer, but from what i have seen they are very active. I do know a few of these guys and in my experience they are a good group of people. I have *no* clue as to their recruiting ... or even if they are/do, but if you are interested in PvP/Fel this would be a good place to start.
My 2c. Hope it helps. I look forward to seeing other responses ... would be cool to see what other guilds/alliances/player groups are active. =)