When Foursquare split itself in half, it was an effort to build up two complimentary features of their platform independently. The Foursqaure app proper would be a Yelp competitor, while Swarm would serve as their check-in module. The success of that move is debatable, but both found favor with users. To help Swarm become a bit more social, Foursquare has updated the app to bring in a private messaging feature. Now, when you want to hang out with someone, you don’t have to ask out loud.