What was the first thing I did when asked to write a post on Foursquare? Download the app and join. When Foursquare was huge around its launch in 2009, I had a Blackberry Pearl which made everything, other than emails and BBM’s, a hassle. Since 2010, when colleagues were contending for mayorship at the office and Yahoo!, Facebook and Microsoft were vying to acquire it, I haven’t really heard much about it. Enter: ad sales.