Second Life has just announced that the Second Life client has been released under an open source license, and they described their move to open source as “inevitable”:

“At Linden, we have always been strong advocates of the use of open standards and the advantages of using open source products. Though Second Life makes abundant use of non-standard technologies, our basic UDP protocol message system for example, we rely on open standards and open source implementations when appropriate and available. Since many of the components that will make up this network are not yet done, we are not publishing long white papers or RFCs at this time — instead, we are giving everyone what we have along with a goal of producing those open standards with the input and assistance of the community that has brought Second Life to where it is now.

Releasing the source now is our next invitation to the world to help build this global space for communication, business, and entertainment. We are eager to work with the community and businesses to further our vision of our space.” (Quote from the Second Life Blog)

I also found it interesting that Linden Lab specified the GNU GPL version 2, rather than releasing it under the GPL and future versions … another company hedging its bets on the still under development GPL v3.

I think this is a great move for Linden Lab, and an astute business decision. By releasing the client software under open source, residents can modify their client experience, while Linden Lab continues to provide the server side code, which is where they make their revenue. Linden Lab is providing a more flexible environment for users, which should translate to additional users, and at the same time, they continue to have the revenue stream required to keep Second Life in business.