I feel like "based" is also being phased out, though "cringe" seems to have more staying power. TBF I feel like we didn't quite have something that really evoked the same emotion that "cringe" does before it came into the lexicon.
I still say wicked, sweet hella and sick and those came from the 80s mostly. It's still pretty common slang amongst punks and skaters and such, we still talk like Bill and Ted.
1337/leet/l33t means "elite" and was a term to show that you were computer savvy or in on internet culture. 1337 H4X∅R would mean, "Elite hacker." According to Wikipedia, it originated on early BBS message boards where users could have "elite" status, giving access to special chatrooms, but I'd say most people encountered it later, in the context of gaming, where it could be used to brag about winning through hacking a game or using exploits, or just to brag about being good at it.
I have a middle aged colleague who still talks with this era of stuff and its so unbelievably cringe. It's not even offensive its just CHRONICALLY UNCOOL
Maybe it's because all popular media is corporatised grey goo now, whereas in the time of thelonelyisland, there was still minor room for internet creativity to be slightly different than very generic.