Follow the Leader/Web Original

"Pegasus: There's so many of them! I can't tell which one is the original!
 * Stories based on the The Slender Man Mythos have become increasingly popular due to the success of Just Another Fool (blog) and Marble Hornets (video series). Some recent cases have abandoned the idea of the characters going in blind and actually mention the existing blogs, with the protagonists assuming (wrongly) that they're just an urban legend.
 * Reviews were commonplace, but The Angry Video Game Nerd and The Nostalgia Critic started the trend of funny ones. Also, Linkara was one of the first with a plotline, and now it's commonplace on That Guy With the Glasses.
 * It is often cited that the ongoing storylines of these shows are what inspired Moviebob to do the same with The Game Overthinker.
 * Yu-Gi-Oh the Abridged Series has had many knockoffs. The creator has even done voices for some of them, as well as lampshading it in his own series, by turning the "Multiply" spell card (which makes copies of Kuriboh) into "Little Kuriboh Impersonators". Yami activates it in his duel against Pegasus.

Yami: That's right, and that means you'll never be able to watch the Abridged Series ever again!

Pegasus: NOOOOO! I can't live without Yu-Gi-Oh the Abridged Series! It's so important to me!

Yami: Don't worry, Pegasus. There's always Naruto the Abridged Series, but we all know that's not quite as good!"


 * AMV Hell. Though the format likely started with Robot Chicken, it was AMV Hell that defined it as a Youtube staple and fan work in general, with notable entries like The G Mod Idiot Box and PONIES: The Anthology.
 * The Homestar Runner web-series seem to have other shows about an Idiot Hero who end-up doing random crap with random characters shuch as Yakkity Yak, The Mighty B and Scaredy Squirrel.
 * After Franchesca Ramsey made the Shit White Girls Say...to Black Girls video, many others followed up with videos following a similar format of a marginalized person performing as a privileged person saying ignorant and bigoted remarks to a person of their marginalization.