[ohstopitu]

I don't seem to understand Matrix/Riot.

It appears to be like IRC, but also integrates with Gitter, and IRC and has a identity federator called vector.im.

[ianburrell]

Matrix is a federated chat protocol. It is like IRC or XMPP but synchronizes history and uses HTTP-based protocol. There are bridges to IRC, XMPP, and Gitter.

Riot is a client. It used to be named Vector.im.