On the downside of blogging, there is always the possibility of being sued. It is easy to tell a friend something like "I think Joe Smith has links to terrorist money laundering." Now, if you put that same thought in a blog and push the "Publish" button, you now have what is literally called in the legal world "publishing" which is a necessary element of defamation.
There is an interesting article in Tech Central Station about the subject of blogging and the potential for liability in the blogging world. In a further twist on the exposure bloggers may have for what they say, how about this: getting sued for what someone says on your blog in a comment? In other words, you didn't say anything at all, but are being sued regardless because of a comment posted by a third party on your blog. This is exactly what happened to Justene Adamec. She has been threatened with suit by the company Infotel based on comments made about the company by commenters on her blog.