Go! Read! This! now! Cc +Michael Tiemann
"Before we open-sourced, we asked everyone why we might not want to open-source. Advisors were okay with it, but thought game developers might have reasons why we shouldn't. Game developers liked the idea, but were concerned it would scare investors. Investors were excited about it, but wondered what lawyers might think. Lawyers didn't see any problems and just told us to run it by our advisors. You can see the pattern here: there's no real reason to keep it closed, but everyone assumes there is.