Ugh… I hate these questions. There’s always so much more to it than I, or I dare say anyone, can fully explain. Let’s start easy, though: What is a clan?
A clan is a group of players who band together into groups where they share information, maybe Role Play (RP), help each other out with learning and getting powers, and more. You do not need to be in a clan in order to Role Play, nor do you actually need a clan for any real reason.
Some clans are based on blood lines. IE: A master vampire and their childer, and their childer’s childer, and so on. Others are based on simply desire to unlive by a certain standard or set of ideals.
Also, clan related, but not clans, are places like the FTA, or other info-based, open-to-all areas, where new and old vampires can learn about the game and make themselves strong with power and knowledge.
As for ‘What clans are there?’, that’s a bit harder. See, there are new clans forming all the time, some clans have disbanded over time, some exist but never become known to those of us here in the Yahoo groups or related boards… There are all kinds of groups. In fact, many clans have become so game-dedicated that they set up massive sites and spend a great deal of time maintaining clan-related places that they can easily overwhelm a new person.
Your best bet is to look around for a non-clan based group where you can learn about the Role Play facet of the game a while before committing to a given clan. Aside from the FTA there is the Phoenix Clan news board, the New and Improved RBB (actually not the RBB, but much better, I hear), the Live Journal community "Lost In Shadows," and I’m sure a whole host of others I have no time or inclination to find a link for. The in-game FAQ pages have an entry about meeting other players and there are links to not only the FTA but many other groups. Check there for some good links.
From there you will figure out how to go about joining one, if that’s the course you decide upon, but I can’t offer much more specific info. Well… Except this: Don’t join the Empire. It was once my own group, but after several poor sportsmen screwed the game up for me, I left it and all the RP stuff. Since I left, the Empire has become a sick husk of what it was meant to be and an insult to the character of Andronicus (that is, my vampire).
Most players were sired by someone, and you might be able to get your sire to help you get stronger, too. I have helped a few of my childer attain their initial Thievery levels because it can be extremely hard to get rolling and I wanted to see them get stronger and more powerful. Look at your options before you go and decide on a certain course of action.