Good question. Many things
Adding to what everyone else has said about the forums representing a side of being online which feels like it has been lost. It's got that early internet message board feel to it where you can get weird without excessive use of the n-word and gore to scare off the "normies" (looking at you, kiwifarms) Otherwise I'd be lurking message boards dedicated to suburban housewives. I still watch public access television.
"The visuals are mad visual, yo."
Skate nerdery and gossip that is top tier. This place has literally changed the way people skate, and for better or for worse has even changed shit in the industry. Plus there's good information on like soooo much additional shit besides skating: sports, movies, cooking (kooking?), music, traveling, cycling, drugs, politics, camping, filming, stand-up comedy, etc. In an era of online spaces where true community/connection is largely lost, it's an online skateshop where you can hop in, chat shit and chill without being ostracized for taking yourself too seriously for saying the wrong shit or purposefully saying the wrong shit to be edgy. Because at the end of the day, we're all here because of the board. Praise the Board(s).
(Wasn't there even a thread about how to prevent balding? Shoutout SLAP Men's Hair Care Club!TM)
Notable mentions:
Stylin On You threads
What made you made you laugh today
pugmaster's memes
Heckride updates
Attiba's Movie Thread
Someone had a sig that read "Come for the skating, stay for the drama." Or something like that. That pretty much sums it up.
(Now, could someone finally tell me the story about Dave Duncan's nachos? Always been out of the loop on that one.)
Edit:Formatting