thorne wrote:
> I tried doing this with font-lock, and was able to do everything i
> wanted, except that the underscores--which i make invisible--leave a
> blank space instead of completely disappearing.
> 
> So, maybe a more focused version of my question would be: is there a
> way to selectively hide strings of text in a buffer such that they
> still exist if you kill the region they are in and yank it somewhere
> else?

Try facemenu-set-invisible .  I found that by running C-h a (apropos)
invisible (People were discussing invisible text a few weeks ago).

Matthew Flaschen