Yeah, you're right of course, but what's nice is that it's easy to figure the sharing stuff out on demand. That is, using GitHub doesn't do anything to lock you in from a sharing standpoint - it is just as easy to go figure out how to share your code after GitHub goes down as it is to go figure it out beforehand. Certainly from a code review and bug report standpoint it locks you in, but so does pretty much every other code review and bug report tool. I'd love to see a distributed competitor to those offerings take off. Last time I said that somebody pointed me to fossil, and it looks pretty cool for that, but it also comes with an SCM of its own.