It makes sense, in a weird way. MMO's are such huge projects that developers are forced to create supporting subsystems to complete it (e.g. Image/asset process

It makes sense, in a weird way. MMO's are such huge projects that developers are forced to create supporting subsystems to complete it (e.g. Image/asset processing and storage system - Flickr, in-game chat and collaboration system - Slack). I'm impressed that Stewart Butterfield is able to look at these systems and recognize which ones could be a viable (and successful!) stand-alone product.