Anyone exploring visualization of code/data (e.g. versus textual source code) should take a look at BV's "Magic Ink": http://worrydream.com/MagicInk (For the "short version", just look at all the diagrams, and read the surrounding text to see what he's doing with each one) It's about determining what a person is trying to find out from (or "questions" one has about) the data being presented (by a webpage, document, or program), and presenting it in such a way that the answers are immediately obvious at a glance. In other words, showing the data is good, but it's only the first step to making that data consumable / workable. He makes a strong case that a lot of "interactive" software would actually serve its purpose much better as a (dynamic) visualization.

It made a deep impression on me when I read it back in 2007. I don’t think any other single source has a dozen quotes in my link blog: http://akkartik.name/?f=MagicInk