Keyboard efficiency in Emacs

Phil Hagelberg posted a comment onto The Graphical Keyboard User Interface:

For ideas on how to improve command discoverability, take a look at how Emacs does things. Every command is named and is invokable via Alt-x and then entering the name (offering tab-completion, of course), and you can look up commands by their name so that their bindings (if applicable) are shown. You can also get a listing at any time of all active bindings. Makes it very easy to explore. The eMate hold-the-modifier-key trick mentioned above is also a great idea.