From Big Journalism.
Righthaven is the leading copyright troll organization in the country. They use Google searches to find text or images that have been used on blogs, forums or websites. When they find something, they buy the rights to that specific article from the rights holder and sue the offending party. Righthaven never offers any warning. In fact, those being sued usually learn about it in the newspaper.
If you’re a blogger, it’s worth the read.