Yeah, he created an OS from scratch to avoid corporate greed of what they charged for Unix.

Which was a Unix clone. Which was the subject of the famous Tannenbaum-Torvalds argument, and Tannenbaum's position in it is pretty much obvious.

To be honest nobody has given me a good view of what emacs actually does…so I’m all ears

It's a nice cozy lisp environment - almost an operating system - that runs on many popular OSes. First of all it's a powerful text editor, but can be used to chat, manage e-mail, read e-news, and so on.