“GitHub has changed the way that people approach development,” says Tom Preston-Werner, the company’s chief technology officer. “They realize that it doesn’t have to be so complex.”
From my experience, GitHub has really revolutionized the sharing of libraries and smaller code sets that you can easily clone and integrate into your own projects. Previously free software was about monolithic standalone projects (and larger code bases) and didn't have the emphasis on smaller libraries. The structure of GitHub has also greatly simplified the process of contributing and importantly accepting code changes to an upstream project.
The other site I use often is "Stack Overflow":http://stackoverflow.com which in one sense further breaks down code in a social question and answer format. With Stack Overflow code is broken down into individual functions, modules and lines of code.
Interestingly the Wired article has a recent picture of Linus Torvalds and it looks like he is running Linux on an 11" MacBook Air.