You don't have to work in public using github. That's the nice feature of DVCS — you can have it all your code for yourself and at the same time enjoy all the benefits of VCS. Using centralized system you don't have much choice - either you don't commit, or you commit and everybody sees your ugly code. With DVCS you can have your private branches and work on your code as long as you want. When you a happy with your work, just push it to the public repo (hosted on github for example). Even more, you can have a lots of tiny working commits and then "squash" them into one big and nice final commit.