We're actually as interested as you in this. Doing data analysis on hipsters was fun, but we're hoping it's the start of much deeper and more meaningful studies. Joining our data with other macro- and micro-economic datasets will be awesome, as will looking at the data over time to build things like cost of living indices.
As to your chain question: they are included, and we're hoping to build a data explorer that lets folks like you filter down the data to make analyses more sound, as you suggest. You can do that sort of stuff right now on our API at http://dev.locu.com/. Let me know if you need help along the way!