every generation loves it's brainrot

The author probably isn't personally familiar with pre-2010 internet jokes so he skipped from 5-year intervals, all the way back 30 years to Monty Python.

In the 2005-2010 era I was seeing a lot of quotes from Arrested Development, Anchorman, Talladega Nights. But the one that really made the jump from TV to internet text comments was the South Park underpants gnome meme, where step 1 was whatever people were doing (in the episode, stealing underpants), step 2 was ??????, and step 3 was Profit!. Meanwhile, some pure internet nonsense around then was stuff like O RLY?, Cheezburger and other lolcat stuff.

In 2000-2005 or so, there were plenty of Simpsons quotes to go around. Internet memes looked like demotivational posters (a take on the motivational posters common in corporate office settings back then). This was the heyday of surreal flash animation, as the Internet didn't really have the infrastructure to have high-bandwidth videos go viral. Stuff like Strongbad, Group X, All Your Base, etc. Text references to bash.org quotes (I put on my robe and wizard hat, hunter2) came from around this era, from what I remember.

Pre-2000, I'm less familiar with. Real Ultimate Power was the first website that made me laugh out loud. But there was less for user posting on the internet: fewer web-based forums before phpbb and vbulletin came along. You needed your own geocities or angelfire page if you wanted to post something that persisted on the web. Usenet and IRC were around, but I don't know the culture.