NebuloChat

Nebulo isn't yet another IRC client. Thanks to the WebRTC technology, when you use it to chat with someone else, your messages aren’t sent to a centralized server but rather sent directly to the recipients, or at worst sent (but first encrypted) via a TURN server.
It's like P2P, but only with instant messages.

The channel-system is managed to connect you with other viewers of the active webpage in your browser.

Nebulo can be setting to work with other signaling system, you can select authorized STUN and TURN servers at the options page, ...

Default signal server will be shutdown at the end of October 2015, so you must be prepared to use your own signal server after this date. A tutorial to do this is now linked in the option page.