If you (or someone else) hasn't managed to look it up, it refers to the days when the internet was primarily used by universities (i.e. home users were not a thing). Every September there'd be a bunch of freshmen who didn't understand the culture or etiquette, who would quickly dissipate as they got bored or figured out the rules. The spread of the internet into homes via AOL in the 90s brought about the same phenomenon previously only observed in September with frosh in that now there are continuously new/ignorant users on the internet who really don't get the "rules".
I use Wikipedia as basically an extension of my brain. I'm in a history program at university, and so many of the names and dates that are essential to it I don't actually know. I realized this when I was writing something last night. I was writing about the English Civil War, and the Restoration, and I wanted to comment on the relationship between Charles I and Charles II, and I went to Wikipedia...and it was down!I had to go to my shelf and get a book. Who does that?
I don't think that's quite the point: I'm sure most people here know how to access the content, but clicking a link and having the anti-SOPA popup appear jarringly reminds us of how frequently we use Wikipedia for information.