Plurk features a horizontal timeline and it lets you share pictures, videos or URLs for web-based articles. The platform stimulates its users to spend more time engaging with other Plurk members through the concept of Karma, which grants you access to more emoticons. This social network can be accessed from iPhones, Android devices or from PC or Mac computers.
A simple chat (slack style) it's enough. Just having the possibility to send messages either single user or team (#channel). But please don't forgive to give an useful appeal to mobile app (worst error of competitors is, have a good app but totally no mobile friendly!) i would expect to have a similar whatsapp or slack app for messaging within the slack mobile app!