The banter about K-On! and Azumanga Daioh had me rolling, because you accurately portrayed about a quarter of anime discussion on the internet.
And Rei's deadpan, male text to speech voice.
And maybe a little of everything else.
I also love how the characters and the backgrounds contrast between one another. The characters distinguishable as a silhouette, which I always love in animation, web or no. The art style, also, was perfect for this kind of comedy. The protagonist looks like if John Kricfalusi and /a/ had a lovemaking session- and it's perfect. I'd enjoy the art even if it was a serious animation instead of a parody, it's real nice on the eyes.
This was a fantastic collab, and I hope to see more quality stuff come from all who participated! I'll certainly have a look at everyone else's work in the credits. I'd advise everyone else to do the same; give these people some recognition.