"or do you mean what pieces of infrastructure would fail if github went down tomorrow." The answer to that being: not many. The basic architecture of git (and

"or do you mean what pieces of infrastructure would fail if github went down tomorrow." The answer to that being: not many. The basic architecture of git (and other DVCS's) is, that everyone has a copy of the full revision history, so if github really went down, you'd see most of the projects there (at least most of the active ones someone cares about) on gitorious or some other git hosting service within a very short period of time, and things would go on with only a minor interruption.