Chat in 2016

It's time to list chat or instant messaging.

I've already written an article (a while ago) but it was more oriented on clients here we are going to look at the servers ... but both are lnked.

The rest is on the French version of the post.
It's mainly a list of solutions with links to web sites, so it should be understandable.

Ask for a translation in the comments, if you need one.