When I was at Laszlo Systems, we did that to revitalize the business, not to turn it off. It was very effective at spreading the word about our product and simply shifted our business model.

It did take some time to instigate a real community around an established code base -- if I were to do it over again, I have ideas of things we could have done better. It's also easier now, I think, with github and the rise of social networks.