In Emacs how do I edit multiple points at once?

Question

There's two variations. I think you can select a rectangle and add stuff to the beginning and end of all lines.

I'd also like to know if it's possible to select multiple points that are on different offsets to where you edit all the points at once. I think Yasnippet provides something similar, but only when you use a predefined template. Something like this.

<div class="">
<a class="">

where i can mark a point on both class things and typing will edit both class attributes. Is it possible?

Answer 1

Emacs Rocks! describes mark-multiple, which does what you want. (Here's their video introduction.)

EDIT: @Lifton points out it has been superceded by multiple-cursors.