Chris Anderson has a great article available for free here "Free! Why $0.00 Is the Future of Business". There are some great examples of "free content" that makes money including Gmail, Ryanair (almost free or very cheap tickets) and Prince’s last CD.
Much like he did with The Long Tail (which also began as an
article), this latest piece cleverly
cross-promotes Anderson’s upcoming book, FREE, which won’t be available until 2009.
The article comes complete with a How-to wiki, How to make money using free content.
Jonathan