Matrix is a protocol for enabling real-time communication between different service providers.
Pro End-to-end encryption
Matrix features end-to-end encrypted chats which are syncronized accross all your devices.
E2E is [implemented in the matrix-js-sdk library and Riot.im client](http://matrix.org/git/olm/about, http://matrix.org/git/olm/tree/docs/megolm.rst, http://matrix.org/speculator/spec/drafts%252Fe2e/client_server/unstable.html#end-to-end-encryption).
Pro Can be integrated with existing communication services
Matrix is designed to support Instant Messaging, VoIP/WebRTC signalling and Internet of Things communication and allows cross-communication between those services. Meaning one person could be using IRC and another Slack for IMs, or one person could be using Skype and another Google Hangouts for videoconferencing.