What about quoting someone else's blog? Can you use a picture you find on the Internet? What is all this "CC" stuff I need to protect my writings or art?
There is a ton of information on the Internet about copyright law, most notably from Stanford Law School's Lawrence Lessig, who currently chairs the Creative Commons project. A Creative Commons license on your blog "helps you publish your work online while letting others know exactly what they can and can't do with your work."*
Mr. Lessig is also involved with the Electronic Frontier Foundation which has published The Bloggers' FAQ on Intellectual Property. I highly recommend this article which addresses issues that arise when you publish material created by others on your blog.