Redditors have basically developed and distributed a set of rules for what they find funny/cool/interesting, and endlessly repeat these same jokes/memes. If you follow the frontpage for any reasonable amount of time, you see the same few ideas over and over. Just about everything is somehow referential to a previous post. It almost feels Pavlovian after a while. Someone will post a picture with an attractive female in it. Someone else will comment with a Gif of a bunch of hotdogs being thrown in her face. Someone else will point out that hidden amongst the hotdogs is a finger. Someone else will point out that every time an attractive girl is posted, all of these things occur. This happens over and over, countless times every day. To call it derivative would be generous, because it's a carbon copy.
Advice Animals (Image Macros with text) seemed to take this to its extreme. The same 10 images are posted thousands of times per day, with a sentence about how some event in the posters life relates to the meme. If you take away the meme, and simply tell the story by itself, its dull and boring. Attach it to the same picture you've been seeing for the last year and half, and it's got 1000 upvotes.
Most of the material on the frontpage of reddit is not interesting on it's own merits. It's only interesting in the context of the thoroughly homogeneous userbase that has been conditioned to respond to the same 15 memes.
It seems to me like an advertiser's dream demographic. A clearly delineated set of rules to engage millions of potential customers. Flip this switch, turn that knob, show this meme, reference The Big Lebowski, and Bob's your uncle.