I am surprised this remains on the front page! For those who are interested, the EFF has a very good FAQ on the subject (1). You should also know about anti-SLAPP laws, which are designed to prevent abusive litigation designed to bully someone into silence (2). There are arguments for a model libel law at the federal level, given the ubiquity of the internet (3). That same ubiquity means you might find yourself sued overseas; but judgments against US bloggers will probably not be enforceable, thanks to a little-noticed bill in congress designed to protect writers from libel tourism (4).

1. http://www.eff.org/issues/bloggers/legal/liability/defamatio...

2. http://en.wikipedia.org/wiki/Strategic_lawsuit_against_publi...

3. http://writ.news.findlaw.com/hilden/20100621.html

4. http://cpj.org/blog/2010/07/us-senate-passes-libel-tourism-b...