Foursquare has 160 employees

"Foursquare’s CEO and founder Dennis Crowley told [FastCompany's Austin] Carr that his company has 160 employees. The old rule of thumb was that you could mentally budget $100,000 per employee in yearly costs, after taking into account rent, insurance costs, and the like. However, given Foursquare’s split profile between San Francisco and New York, I think that the old rule is outdated and far too conservative. Let’s be polite and assume that the figure is $150,000 per worker, giving Foursquare costs in 2013, for personnel alone, of $24 million."

Source:  TechCrunch, 6th August 2013