Thanks! I came across this kind of app for the first time in January (GrandPerspective, WinDirStat, DiasyDisk, TreeSize, etc.), and I've spent a lot of time thinking about/working on making interactive/visual trees in the past, so I really wanted to take a crack at making the best one I could.

Here we are many months later and I'm finally starting to be pretty happy with the results. It's taken many iterations, but it is quite effective from a usability perspective now.

I'm starting to put a little thought into what other kinds of hierarchical data it might be useful for exploring...