Definitely stay away from the Paris Hilton/Britney Spears related stuff.

Those usually get deleted as soon as a mod can properly check the offending site, bookmark them on their own computer, then delete them from the forum.
If you're just getting started in the subject, I would suggest reading any thread that alludes to starting out. Also, anything related to equipment issues, especially wasters and sparring. I would post some links, but there are alot of these sorts of threads and they all say pretty much the same thing.
Try to get in personal contact with an ARMA member or study group in your area if you're interested in pursuing this subject. You'll learn alot more from seeing and doing it for real than from only reading about it. If you don't have anyone nearby, try to just set a weekend aside for a roadtrip to a study group session. Contact them beforehand so they know you're coming and to confirm time and location.
If you're talking about general conduct of the forum, just read the forum rules and then to see what is frowned upon you can look at the locked threads. Generally just stay civil, on-topic, and have a modicum of humility and you will have a good experience here.
I've been in ARMA for less than a year and feel that I have only recently emerged from the "completely lost" stage and am now in the "slightly discombobulated" stage. The times that I really felt like I had made some great leap was when I got to train with others. There is alot of material out there, alot of different ways to approach it, and alot of opinions both well founded and not so much.
I hope this addresses what you were asking. Welcome to the forums!