The free GitHub account allows you to create public repositories. This means that anyone is able to search for, view, and clone your project from GitHub to their own desktop. This is the central idea behind GitHub. This is obviously a key factor for indie developers and corporates that don't want to spend money. Corporates can afford it more than an indie developer, but I think that some companies prefer to roll their own, rather than use a service provider hosted in the cloud somewhere. This means that they prefer to keep the source control under their control by setting up a source control system on their own corporate servers. Having GitHub as an option for indie developers is an awesome solution. For those that require private repos, the fee isn't a stumbling block either.