I have a free Github account, because Github has become very popular and I've read and seen things that insist I must be on Github. But I've never used it and I still don't get it. It seems to me that the purpose of Github is to archive and share open-source projects. However, open-source is not the only way to develop code. I don't actually work open-source because nobody has ever offered to pay me for writing an open-source project.
In fact, every single commercial project I've been paid for places me under a non-disclosure agreement. The code belongs to the client, not to me. Therefore, I could never post my client's code to Github. And in many cases, I have to use the client's version control. In other words, I post my commits to the company's Perforce, VSS, or other system.
So...please explain to me why I "MUST use Github"?