Utility is number of users times how much it helps each one. This is the sort of app that helps a very large number of people, but only briefly each time. It's sort of like Google in that respect. I'm not sure how many users Bump has, because this is one of those companies like Dropbox that grows so fast that the last number I heard is always way off, but many millions. They may have more users than anyone else we've funded.

They're also like Google in that most of the hard work is behind the scenes, which tends to affect users' perception of how much the app is doing. To an inexperienced programmer it might seem like it wouldn't be hard to build a search engine-- and in fact it isn't hard to write a crawler and build an index. What makes it hard to build the actual Google is (a) the scale on which they operate and (b) the refinements they employ beyond merely searching an index. It's basically the same with Bump. They have to operate on a large scale, and to work reliably they have to deal with all sorts of weird edge cases.