"Never Gonna Give You Up" by Rick Astley.
"Rickrolling" was the most baffling and pointless fad that has ever plagued humanity. It was perpetrated entirely by idiots who mistake non-sequiturs for wit, and confuse wasting their fellow man's time with comedy.
Rickrolling was how people too morbidly obese to put a bucket on top of a door interpreted the prank. Fuck Rickrolling, fuck everybody who's ever sadly tried to pull off a Rickroll and fuck you if you think it was ever funny.
Star Wars Kid
In a lot of ways, "Star Wars Kid" invented viral video. Now, since this is the Internet, I'm positive someone will correct me, but to my mind, this video of a kid flailing around in his garage was the first YouTube clip to spawn many thousands of remixes, re-edits and parodies. It was the first one I heard talked about at the water cooler I frequent (I work from home, so it's mostly just me leaning against it talking to myself), and also the first one I saw referenced on Arrested Development (the single most important cultural index of our time).
Seeing the clip's meteoric rise was the thing that made all of us struggling sketch comedians mutter, "Oh, so you just film yourself being retarded. That's... that's all the effort it takes. Just a cat or a baby or a retarded kid. The world's most exciting new media delivery apparatus is just America's Funniest Home Videos without Saget." And though we've muttered that into our scotch every night since, it's not yet ceased being absolutely true.
"Charlie bit my finger."
A toddler being adorable for 56 seconds, 140-million views. While the Internet sprang to life in the 90s, it was still for the young and the geek. The 2000s was when your mom joined the party.
Now your grandma is your Facebook friend and grandpa has a Twitter feed and you're getting forwarded pictures of adorable animals five times a day.
"Two Girls, One Cup."
This is a threshold-crossing moment. We, as the Internet, hit a milestone in desensitization. I'm [fortunately] old enough to remember a time before Internet pornography. My people were raised on Victoria's Secret catalogs, blurred Cinemax porn and episodes of Buffy the Vampire Slayer where Sarah Michelle Gellar wore a low-cut tanktop.
If someone would've asked me at 12-years old if I wanted to watch two strange women kiss and eat each other's shit and vomit--and this is important--erotically, I would've said "No" because I, like everyone else at the time, only needed to see at least one boob to be satisfied.
We have now entered a time where not only eating a shit sundae with vomit sauce is considered a sexual act, it's the only sexual act that can elicit a response of any kind. It's the only kind video on the Internet that can make us feel anything anymore.
"Boom Goes the Dynamite"
Cringe humor dominated Western comedy with British and American Office's, Borat and Curb Your Enthusiasm. But nobody executed the art of the face plant as well as the Boom Goes the Dynamite kid.
Named for the Sportscenter catch phrase he spits out 90 seconds after it should've been clear that he'd never be allowed near a teleprompter again, he delivers the most hilariously earnest, two minute long word salad captured on film in this or any decade.