By the way, well done on sameroom. I came across your product while working on the stuff I mentioned and it looks like an incredibly useful thing. I really wish you would open source it, though. (Or at least open source some libraries for talking to the protocols you deal with. Especially Hangouts.)
We're so paranoid about getting shut down by Google (Hangouts, no API), Microsoft (Skype, no API), and Facebook (Messenger, no API) that we're not only not open sourcing any of our implementations, we're not even providing a commercial API in fear of having to deal with some form of abuse.
That said, the night is young. We hope to eventually gain enough leverage to get the big guys to listen to us.
Can I ask you some details on how you went about working with Skype and Hangouts? Did you do the reverse engineering yourself? These are protocols several popular open source projects have been trying to support for years and haven't succeeded.
Can I also ask you about your tech stack/languages you used for Sameroom?
Our magic weapon is Erlang, which is a wonderful language for working with protocols, and a wonderful runtime for working with many things happening at the same time.
The other magic weapons are the Cowboy webserver and the Gun http client -- both written by Loïc Hoguin. Loïc doesn't work for us, but we've been sponsoring him financially for over two years (https://medium.com/@abs/what-we-learned-from-sponsoring-an-o...).
Our frontend doesn't really matter as much, since it's just a dashboard, but we use TypeScript with Flux and React (it's been great).
Nobody is getting sued yet, and Pidgin supports all of them nowadays.
http://www.theverge.com/2014/4/21/5635488/msn-messenger-vs-a...
And all IRC implementations are "interoperable" in the sense that a single client that implements the protocol can connect to any of them, this chart seems to be padding things a lot by calling every IRC server network a "chat service". A number of them also have or have had interconnects with each other in the past.
