I really do not remember. My best guess it was selling signature links on Digital Point.
I had started with no money online, it was a real struggle then :P
For me it was doing a really pathetic logo for which I got paid $3 :P
My first ever job was writing a sales page, which, even if I do say so myself, I thought I did an excellent job considering it was my first ever piece. I got paid just $10 for it, but I was so happy at the time :P
I earned it through AdSense.
I wrote the help documentation for a 3D graphics game engine.
I believe mine was also from AdSense, when I was a gamer, I setup a website for my clan and got my friends to click the ads lol.
I am surprised no one said forum posting :P
Selling forum signatures on Digital Point