I'm surprised that I have just found out about this site. You create simple one-page topics that you are interested in and if people view your page, then you get money.
It's the simple version of making your own webpage, and adding adsense to it. But, you know you will get visitors to your page at http://www.squidoo.com/.
My first 'lens' - http://www.squidoo.com/socbee/