Such opportunity is at once exhilarating and completely overwhelming. With a data set that big, where should I start? What should I focus in on? I spent a week just reading about other community research my boss threw my way and brainstorming long lists of ideas. Finally we decided that it would make sense to start with an investigation of how various groups form, grow, and, in some cases, die -- in itself a complicated question, of course, but still something around which we can focus investigations. I imagine that once we start playing around with the data, other research directions will become apparent. This seems to be the way I like to work anyway, whether in research or programming or usability: I assume that it's impossible to anticipate everything that I'll want to do, so I just jump in early, get my hands dirty, and iterate. I'll do my best to write periodic updates on what I'm learning.
Oh, and the title above is my working moniker for the project. Tipped hat to the late Jane Jacobs (one of the main inspirations for my undergrad research project on "healthy cities").