Vimari is a Safari extension that provides vim style keyboard based navigation. This lets you control Safari from your keyboard instead of having to use your mouse to open links, scroll, etc. The code is heavily based on vimium, a Chrome extension that provides much more extensive features.
Vimari attempts to provide a lightweight port of vimium to Safari, taking the best components of vimium and adapting them to Safari.
Vimari is open source, and available on GitHub.