One of my favorite but little used emacs features is rectangular editing. It's little used because I don't need it all that often. It's one of my favorites because when I do need it, it's just so amazingly useful.
The idea is you can mark a rectangle of text, cut it and later paste it. This means that if you have three columns of text:
a b c d e f g h i j k l
You can easily mark the middle column (b e h k) or even just the b e and h, cut it and paste it elsewhere as a rectangle. You can also open up a rectangular region (filled with whitespace). There are a couple of other niceties but that's the basic idea.
Here's a link to all the functions:
And the video:
Enjoy. Relevant links:
Video series overview page: