From Shepard Fairey to Seth Godin, there are lots of examples of people who have given their works away for free in order to spread an idea. But here's proof that it works if you just want to make more money. (Paying attention, music industry?)
The boys of Monty Python, rather than take legal action against people posting their clips, decided to do the YouTube crowd one better by making their videos available in an official Monty Python channel in really high quality versions. (Since, well, they kind of had access to the sources.) The caveat, as they explain, is that they want you to go buy their stuff. And it's working. To the tune according to Fast Company, of 23,000 percent. That's a lot of sparrows and coconuts!!
And of course, their explanation video launching the channel is classic Monty Python. These guys understand the value of their brand and have always stuck to it. Kudos to them for taking a non-litigious approach that has benefited them and their fans.