While they have plenty of limitations, tag clouds are excellent for outlining the relative importance of many concepts at once. They're also visually very attractive, a lot more eye-catching than a uniform paragraph of text or a bullet-point list.

I'm having trouble coming up with any arguments on what a 3D tag cloud is actually good for (if pushed I'd mumble something about using the extra dimension to show time information) but boy, is it it pretty! Awesome job by Roy Tanck, and thanks to Logic Nest for finding it.