I use it for snippets of code that I want to save (and, maybe, make publicly available and link to) but aren’t serious enough for a repo. Here are some examples from [my gists](https://gist.github.com/Sidnicious):

- https://gist.github.com/1173880: A chunk of code to get information about running processes.

- https://gist.github.com/1082933: A little JavaScript function to decode quoted-printable encoding

- https://gist.github.com/842476: A chunk of code that blocks (I wrote it for a startup daemon) until the OS’s network stack is ready.

- https://gist.github.com/c980470f5ef244c4b4d3: My and a friend’s solution to the last level of Stripe’s CTF (may not be the final version)

- https://gist.github.com/2586751: A patch against a JSON library that to make it handle escapes in a spec-compliant way.

…Some of them are useful as-is, others are useful as reminders of how I dealt with a particular problem in case I run into it again.