I have no idea how I stumbled on to MeFi -- I recall that I had lurked for a long time before signing up because so many of the usernames were early-internet Famous People and I was a bit daunted. I was in love with the internet then, just like I am now, and I wanted to become one of those People Who Make Internet Things.
Now I am, and I don't think I would be without Metafilter.
Rick Gleason and Bali
Like I said in this Metatalk comment a long while back
The thread about the Bali bombing, in which I discovered that my friend Rick had been (it turned out, fatally) injured, and the thread posted after he died changed a lot of my thinking about community on the web (for the better), and made it certain that much as I get frustrated sometimes, I don't think I'll ever want to leave Metafilter. The site itself and a lot of people here are very close to my heart.