The latest startup, two year old Euclid Elements wants to provide real world info to brick and mortar stores akin to the analytics available for websites (who visited, for how long, what did they buy....). How? By putting in a sensor that captures unique wi-fi-based info from pedestrians. The phone must have wi-fi and it must be on for you to be tracked. But, don't be afraid, all the data is anonymized and you can opt out on the company website. (I opt out by not turning on wi-fi, done!)
The data, including how many people passed by, how many came in, for how long can help partners, like launch partner Philz Coffee, determine tactics to draw in people or sell food to those who are staying for 45 minutes around say, lunch time... Launched in 2009 with $500,000, the company just got in first round funding of $5.8 million, which was led by New Enterprise Associates with Triple Point Capital and Harrison Metal.