That's what XMPP is already doing.

I usually dislike introducing yet another standard, but Tox has some features that XMPP won't provide. VoIP support out of the box, without the need for an extension that may not be supported by the client. Also, afaik it's truly decentralized, without the need for a server for the actual communication.

> VoIP support out of the box

True, but do you think it's easier to deploy an extension that already exists and just lacks implementations, or to create a whole new protocol from scratch ?

If you look at other successful protocols, you'll also see that some features we rely on were bolted-on as extensions to protocols that were defined before, such as DNS, IMAP, HTTP... Not that it's an excuse to do the same, but it's expected.

> it's truly decentralized, without the need for a server for the actual communication

I don't think that's not something you actually want.

- How do you send a message to someone who's offline ? You don't, you have to wait for you and your contact to be online at the same time.

- How do you traverse NATs ? You have to craft all that messy code, and it's not even guaranteed that it works... you're going to need a "known anchor" for everyone to connect, just like what we see with WebRTC. If you're aiming for a one single protocol, there's no way around that. By the way XMPP can do signaling over XMPP and actual communications over direct, P2P links (such as SOCKS5: http://xmpp.org/extensions/xep-0260.html)

The sad state today is that many clients still haven't implemented Jingle, but at least there's something to start from.

Your points are well taken, but this is unfortunately a sacrifice that needs to be made in the name of security. While partial centralization would solve a few problems, it would also introduce weak points in its security model that three letter agencies would be quick to exploit.

Tox actually does NAT traversal quite well I've found, and it does support SOCKS5 connections out of the box, albeit through TCP relay nodes rather than direct P2P.

Does XMPP support video?

Edit: yes.

https://xkcd.com/927/ is the kind of situation we need to avoid.

Yes, XMPP supports video. It even has several incompatible ways of supporting video to choose from, most of them called Jingle.

XMPP/Jingle worked, although the quality wasn't very good. You could make video calls between Google Talk (also on Android) and Empathy, the standard GNOME XMPP Client.

XMPP is a rat's nest of extensions from which everyone picks a handful to implement creating a very incompatible ecosystem.

And SIP before that (XMPP being 'superior' because XML)

SIP always seems much nicer to me; meaning I can actually understand it in close to realtime if necessary.

SIP in XML would actually be a massive improvement, because you'd have sane parsing rules.

Is XMPP distributed like tox?

Distributed as in peer to peer? No. Distributed as in federated, everyone can run a server and talk/interact with people on other servers, transparently? Yes.