I never bought into any of the early online service providers, because I had Internet access during college, and afterward, because I worked at one ... not that there was much to see that wasn't completely text-based, or so I thought; I didn't find Mosaic until about 1995, and then I was hooked.
When the first messaging clients showed up, "littlebluedog" was already taken on AIM, so I became "petitbleuchien" instead. I did manage to snag "littlebluedog" on Hotmail, my first web-based email account, then when Yahoo! email got popular, I switched over. However, "littlebluedog" was not available, so on December 10, 2001, I grabbed what I figured was the next best thing: "little_blue_dog."
I try to claim it whenever something new pops up, so I'm "littlebluedog" here on LJ, on gmail, Wiki, PayPal, eBay, del.icio.us, digg, and a host of other websites.
I don't know how often (if ever) Yahoo! purges inactive accounts and frees up potential usernames (I check every few months), but I mistakenly tried to login this morning with "littlebluedog," forgetting the underscores. Instead of the standard "incorrect password" message I expected, I received an "are you trying to set up a new account?" query.
So I'm now "littlebluedog" on Yahoo! email.
gmail is slick, but I have some issues with the interface and still prefer Yahoo! email, so for now, I'll stick with it. Seven years is a long time, and it'll take some effort to change a lot of my site reg info. I'll keep checking the l_b_d account, pretty much because I get a perverse joy out of being in the vanguard of spam and hoax mail recipients.