How The Huffington Post uses real-time testing to write better headlines

Having a good bit of traffic allows The Huffington Post to a/b test article headlines for 5 minutes in order to pick the winner with the most click-thrus. We have done this on client sites by testing copy in different content modules but the tests run for a much longer period. It would certainly be fun to be on the data side of these tests and to see what works best. Anyways, there are some good links in the article to some other a/b test cases.