I thought: why don't we create a user called StackExchange on GitHub? And then create a repository for each programming site on Stack Exchange. Users will be able to post codes there and embed gists here, if they have GitHub accounts and if they want to.
Good codes will become popular on GitHub, and snippets will have better google ranking. Users will definitely be more encouraged to write good code. They can brag about having many users on GitHub. I think it has many advantages, and I can't think of disadvantages.