I found DU soon after it went live, while looking for Bush jokes online. The search led me to EarlG's great Top 10 Conservative Idiots.

I was hooked immediately.
But I didn't yet own a home computer (and would not until the following January) and was able to only take short peeks while at work. Bummer. But I regularly checked out the site and found myself reading the forums. At the time, I was such a newbie to the internets that I had never previously seen any kind of discussion forum, let alone posted to one.
But, after 9/11 (the day no one at my company was successful in getting online for anything, even though we have a T1 line -- very little work got accomplished that day and ultimately, we were sent home early), but traffic must have been insane. That got me checking more often.
Then, the day after we started bombing poor Afghanistan (that was a Sunday and so I had no internet access from home), I could wait no longer. I knew, instinctively, that the United States was embarking on something that would go horribly wrong. And, sadly, I was proven to be correct.
I joined DU on that Monday and have been here ever since. I've met some amazing people here (both online and in real life) and some...well, least said, etc.
Special callouts to my dear friend Andy Stephenson and my

BDC, who would be forever unknown to me had DU not existed.

to DU.