Wrought Iron Style : This is just a visual variation on the
block-style fractal maps. Here the emphasis is on the fractal tree structure, so the color blocks have been reduced to small color circles, and because HTML5 makes it easy, the connectors are now splined smooth curves.
It's important to note that what's conveyed here is
distance, not
importance. In the 100 Cities data, Perth is at the top level not because it's important but because it's far away from everywhere else. London is (arguably) more important, but because it's nearby many other cities in the dataset, it gets placed down on a branch. Similarly, the Third Musician in Romeo and Juliet is conversationally very far away from everyone else (he has one line, "Faith, I know not what to say."), so he's at the top level, as far from all the other dots as can be. Meanwhile Romeo talks to everyone (Juliet especially) and so he's 8 clicks down, very deeply clustered. Whether or not this is an appropriate geometry depends on what information you have, and what you want to convey. But in any case, in this version the branches have been rotated to center-weight the diagram as much as possible, to have visual weight (branches with many leaves) brought to visual importance (the center).
As noted elsewhere, all the graphics are HTML5 canvas and so exclude IE. The zoom effects are smooth in Safari and Chrome but choppy in Firefox.