I find myself using this site to prototype and test my markup. I don't need to rely on my usual dev computer. I can jump on any computer to code away. Platform agnostic since all you need is a browser.
It's also a good way to get a collection of snippets going for reference. You can check out my collection of snippets hosted by JSFiddle.
Git is an ideal way to manage code for any kind of project. Ever since I've started using git, I've grown less dependent on ftp. It's quite a mental juggle if you're having to think about numerous files that you want to push, upload, overwrite or delete. Why not automate the process and let git keep track and deploy the files for you? Well, let's git going! Lame pun intended.