Aharef has a nice app built using Processing (an open source visualization framework) that graphs the HTML of a webpage.
HTML consists of so-called tags, like the A tag for links, IMG tag for images and so on. Since tags are nested in other tags, they are arranged in a hierarchical manner, and that hierarchy can be represented as a graph.”
This is what derivadow.com looks like.
And the BBC’s music site:
And loads more graphs on Flickr.
Derivadow 
Check out the graph for Google’s homepage. Nice and small and simple.
http://www.live.com is nice and simple too. I do like the app – it’s interesting and the animation around the graph unfolding is cool – shame there’s not a practical use for it.
thanks a lot for your help!