I agree that it's useful if there is a way to customize a program's "markup". Once the markup is there, though, anything can display it. For instance, in an x

I agree that it's useful if there is a way to customize a program's "markup". Once the markup is there, though, anything can display it. For instance, in an xterm-color or linux terminal, you could type something like ":colo darkblue", and you'd still see custom colors. This is using vim's color path (e.g. "/usr/share/vim/vim72/colors", "~/.vim/colors"). But the colors are there because the text includes things like "make this bold", or "make that green". And in a terminal, I might have customizations for this markup that apply to everything, which can be nice. For instance, maybe I make all bold text red, and that holds in everything from editors to man pages. It's convenient to not have to make these settings in every program that I run.