Well, if you're using it like it's supposed to be used, all of it is accessible by a third party and its availability depends on them. It will all be potentially scrapped (meaning it will be). You are essentially outsourcing the hosting as well, with its pros and cons. I'm heavily biased against that, so it's not only a github thing but a "cloud computing culture" thing. I only use other people's computer when using my own is a real problem or it's just not feasible.