FourSquare splits checkins to its new Swarm app, Google splits document editing from Google Drive into a separate Google Documents app and now Facebook splits messaging away from its regular app into the separate Facebook Messenger app. My question is, why? What is the drive behind all this splitting? Isn't it more sensible to have one app that does it all than to require people to download several other apps in order to retain functionality the first app once had? The FourSquare split to Swarm was a dealbreaker for me and I now use Facebook to checkin instead. I'd ditch the other two, but am sort of locked in with them.