
I doubt you can run programs from it, but I could be wrong.
The main reasons for github are version control and collaboration. As you're improving your code you basically "save it" with this opensource software called
git, and if something messes up like you're code stops working for some reason or you lose your code you can go back.
It could potentially save you dozens or even hundred of hours of wasted time. With git you can make a repository of different versions of your code. (Kind of like video game saves.)
Github (and other sites like
bitbucket) allows you to clone the repository on your computer that you made with git to a place online. That online repository is always accessible even if your computer messes up or whatever. You can also collaborate with other people and code together. If something bad happens to your program or website you can also back track. You can also just "fork" other peoples code (basically clone it) and customize it to fit your needs.
I use both github and bitbucket (not really any major differences IMO). I use them both for version control, but I'd also like to collaborate with someone and make something simple to gain experience.