What's this word expansion thing?
From firstname.lastname@example.org Tue Jul 2 09:06:23 1996
I just now discovered emacs has word completion. I guess that's for when you have to write one of those papers in which the first letter of every word starts with 'e' or something.
To use it, just type out the beginning of the word, and type 'ESC-tab' and it will prompt you with a list of possible words to complete. You just type the number or letter of the word you want.
You need to be a text-mode buffer for it work. If you are in a lisp-mode buffer, it will complete lisp functions for you. It doesn't complete C code in C mode however.