Very neat idea, and as others have said, cool animations! However, I'm not sure I buy the premise that "Social media signals can be used to give a rough picture of foot traffic around places of business," at least in general.

I can believe it for restaurants, hotels and popular hang-outs. But thinking about churches, strip clubs, the urologist, etc., I wonder if there are "blind spots" or other areas of low-quality data. Or even areas of poor cell coverage?

Maybe in most cities there are enough other places around that people frequent to cover over any blind spots? I'd be interested to know whether they've found any places like that?