I generally have not thought about how Dropbox spent its money until I visited the web interface, which has been redesigned for the tenth time over, and remembered that there’s still no way to see how much space your folders are taking up.

I guess I already know roughly how much space they're taking up since I just check how much space I'm using in my dropbox directory on one of my computers. From my perspective, Dropbox basically has no User Interface, but a fantastic User Experience.