Found this video via a Mashable article. I rarely look at anything on Mashable anymore but thought this was worth the share. 

The prank that this coffee shop pulls off with such a minute amount of data is hilarious, and slightly scary. What they accomplished, from a tech perspective, isn't complicated at all. However, this video makes you think about how much info is out there about our lives that we don't think about. 

Full video below (if you're an email subscriber, you may need to click through to see it). 

On a completely different note... 

while clever, I wonder if this is a smart branding move by the coffee shop. I've seen videos where companies play pranks or "outwit" their customers. Do you think that entices people to come back? Or do you think that brands/companies that make their customers feel smarter have better long term dividends?