[beatgammit]

This isn't very common, but I was trying to build a common CLI tool in the browser to use in an internal application at work. I compared output from my implementation with the CLI tool until I got to feature parity (and to clear up confusing things in the spec/source code).

For other things, I've used it for examining network packets (binary protocols), mystery files, and proprietary data formats. I've also used a hex editor to hack executables (most notably hacking in a dark theme into Unity3D).