org-mode speed keys

I use org-mode in Emacs, and today I discovered "speed commands":

org-use-speed-commands is a variable defined in `org.el'.

Its value is t

Documentation:

Non-nil means, activate single letter commands at beginning of a headline. This may also be a function to test for appropriate locations where speed commands should be active.

So, when you put your cursor at the beginning of a headline, then many commands are accessible by a single key.