>>20
It's interesting that you should mention SA. Reading it today, I agree that the posts are generally high quality, but I also think that a lot of the irreverent zaniness of its earlier days has been suffocated. In some ways, I think 4chan has some of the qualities SA had back then.
SA gave birth to numerous photoshop memes as All Your Base, tourist guy, and image macros in general. They used to be a major hub for filesharing. For a long time, they were considered the "center" of internet comedy. Then gradually they started charging for registration, and the rules for banning got more stringent. Periodically they have also closed it from viewing by unregistered users. This undeniably raised the quality of posts. The raised barriers to entry made them a walled-off community of sorts, isolating themselves more and more from the rest of the internet. However, I think this snuffed out the "spark" responsible for some of their most well-known work. I can't remember the last time they were the source of a popular fad.
Meanwhile 4chan with all its shit combos, failed gets, and catchphrase parrotting, is pumping out stuff like rickroll(RIP). I'd also like to say Chocolate Rain, but it's impossible to know if that would have become popular regardless of 4chan finding it.
So raising the bar can increase quality, but raise it too far or too broadly and you risk stifling creativity. I think a good balance is sticking to the illegal stuff as they are now and also spam. Spam including both advertisements and mass repeats of copypasta.