I might have been dimly aware of MetaFilter in grad school (I was in a class circa 2002 with somebody who was doing some research on SlashDot, so it may well have come up then), but I was waay too busy reading for grad school to do any fun web surfing. My main reading started after I finished my comps, around 2004, when my husband would send me the occasional link to a MeFi post he thought I would like. So basically, it's all Horace Rumpole's fault (just like Minecraft).
So this thread was the one that I read that really made me a regular reader of MeFi (though I would not get around to actually joining until about a year and a half later). As an academic, I simply could not resist the sordid tale of a plagiarist getting smacked down by the internet. Between the MeFi comments and the comments on the linked blog, I was up until 4am reading, until I finally peeled myself away, the beautiful blue background burned into my retinas.
Sometimes the discussions are frustrating, sometimes people seem to be talking past each other, and often we rehash the same old thing over and over. But one thing I can say about MetaFilter: It's Never Boring.
Welcome to puberty, MeFi!