New York City marks April 16th as Foursquare Day, Mayor feeling good about his chances

16 is the product of squaring four, so naturally the date of April 16th is the most logical one to be called Foursquare Day. Just why such a celebration should exist is less obvious. As it turns out, a grassroots movement of Foursquare users built up steam around the idea of dedicating a day to the online check-in service, that concept then filtered through to Foursquare's founders who decided to go "100% in on this," and now, somewhat surprisingly, so has New York City Mayor (the elected one) Mike Bloomberg. As Mike sees it, Foursquare represents a fine example of NYC's startup-friendly environment, which is why he's giving it and its heretofore informal Foursquare Day celebration the official NYC seal of approval. He even went so far as to deliver a Mayoral Proclamation to the Foursquare offices, which you can see for yourself after the break.