Today, I got a Creative Commons License for my blog. (If you scroll down to the bottom of the page, you'll see a link to it.) It's the Attribution-NonCommercial-ShareAlike 2.5.
It disallows the use of my work for noncommercial purposes, but allows people to modify and reuse it, under certain conditions. (I'm not good at stating this "legally", please look at the above link.)
Licenses like these are meant to expand upon copyright, so as to help "free use" of creative works. This article has much information about Copyrights and "Copylefts" (as these licenses are called.)