I've recently been messing around with Mutt a lot on my server (I hope to post about that soon).
I got so used to using the Vim-style keybindings to browse my mail that when I finished hacking Mutt and switched to Google Plus, I automatically started using the j and k keys to scroll through posts - and it worked.
The / key also puts you in the search box. There's a list of other keybindings here.
So then I tried it when I moved onto my Google reader, and j and k worked there, too. There are several other ones.
I think this is pretty cool and useful.