Hi there, Twilit! Welcome to PC yes! n~n
Well, to start, I'm sure you'll have many happy times around here. Plenty of people to get acquainted with and friendships to make so of course you'll end up with some fond memories. :)
It's kind of hard to answer your question though.. but what sticks out most as being "different" here is the 30 day bumping rule, which says you can't bump threads that haven't had a post for over 30 days. Some sections changed this rule around a bit (like Pokemon Clubs, I believe) but generally it's a rule that applies over the entire community. Some new users miss that and end up posting in old threads only to have them locked. Apparently it's a rule that isn't very common around other bigger forums - or so I was told - so they assume it's fine and do it. But it's right there in the rules so there shouldn't be much of an excuse to do such, right? :3
And of course, usually all questions in Pokemon-based sections go in the appropriate Quick Questions threads. So if you need help with Black 2, you'd go to the Fifth Generation board and make a post in the B2/W2 Quick Questions thread at the top of the section. That's something a lot of other newbies miss too and instead end up just making threads, which usually end up answered with a redirect to the quick questions thread, then locked. This all might seem confusing but you'll get the hang of it quickly! :D
As for clans.. we have clubs here, yes! We have a section called
Pokemon Clubs and
Fan Clubs & Groups for all your clubbing needs. Pokemon Clubs is where all the Pokemon clubs are (of course!) while Fan Clubs & Groups is for all other clubs. If you don't see a club that you like there, you can look into creating your own!
Overall we're a pretty friendly place so don't be shy to post around. If you have any more questions, just private message a staff member! We love to help~ sorry for rambling, hehe.