Last year, after Twitter began moving away from a purely chronological feed, Rochko began building the back end for what would become Mastodon. Instead of building a unified service, Rochko envisioned something more like email, or RSS: a distributed system that lets you send public messages to anyone who follows you on the service. Anyone can create a server and host their own instance of Mastodon, and Mastodon works in the background to connect them. (source)
We’ve talked about how great VSCO is before, but it deserves another mention here. VSCO is a community of creatives from all over the globe coming together to connect and share their work. Aimed at people with a keen interest in photography, this platform attracts photographers working at a high level, so the work you’ll see here is of a great quality and is bursting with innovation.
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!