These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Discredited Meme: Nearly every meme becomes this after a certain amount of usage and timenote from a few months to a year on every board but /b/.
There are some memes that everyone is sick of hearing but persist long past their expiration date anyway; see Shiggy Diggy.
Attempting to predict one's post number is a bannable offense, and the classic "dubs" were removed on certain boards.
Any meme reddit has gotten its hands on instantly becomes this. If it is still used, it's used ironically.
Eternal September: Summer sees children on vacation, which leads to an influx of new users every year around that time. The problem is that this heavily impacts the quality of the site, and some "summerfags" stay afterwards. Then there's the group of people that believe "summer" doesn't exist, and that the boards were always terrible. The truth seems to be somewhere in between.
Hypocrite: 4chan complains about Reddit stealing memes, yet a few memes (That Feel) are used on the site that aren't original. Unlike Reddit, however, 4chan recognizes they didn't create the memes and people generally know its origin (Krautchan).
Humans Are Bastards: 4Chan and Reddit are most notorious for their hateful vitriol, casual racism, sexism, and homophobia, an uncontrollable amount of cyberbullying, encouraging teenage suicide, and being seen as the nucleus of the most rotten aspects of internet and fan culture. The boards are treated with heavy scorn and disgust by those who do not frequent them.
Knight of Cerebus: The arrival of a large number of casual users, facebook users, children, reddit, and 9gag to 4chan has certainly lead to disruption to the point where it can be difficult to have threads anymore.