Github is the heart of open source. It is the reason I can call myself an Open Source Contributor. It contains a wealth of information in the form of millions of programs' source code. Additionally, it is an efficient means for collaboration, allowing someone like me to make contributions to huge projects easily. The site itself makes working with Git extremely straightforward and helps to exemplify why certain git workflows are useful. Github also has a wonderful API that has made tools like the Hub CLI possible.
"Talk is cheap. Show me the code."