If you actually put the content of the messages on the blockchain itself it'll become ridiculously expensive really fast. Furthermore if you actually wait until a message gets mined to be accepted it's not going to be exactly "instant" messaging.
What would be the point anyway? A dedicated peer-to-peer messaging network that doesn't need to keep track of the entire history of everything seems much more appropriate. IRC comes close to that with its federated architecture, although I suppose a completely seemless bittorent-like peer-to-peer chat using public key cryptography for message authentication could be pretty great.
My original comment was a little bit sarcastic, but seriously - why not? I understand that a single blockchain will not handle global scale messaging. But a set of federated installations, could that work?
"My original comment was a little bit sarcastic, but seriously - why not?"
Because in engineering, the question is not "why not", but "why". Blockchains are not the default answer. What positive virtue is blockchain going to bring to your IM system that is not better attained by a non-blockchain-based solution?
If you can answer that, great. I'm not saying this has no answer. I'm just saying it's the real question.
If you are going to say the word "federated", then from what I can see, trying to do "blockchain" at that point isn't all that helpful and likely to be worse and harder than just trying to develop a federated system, a sufficient challenge on its own that doesn't strike me as greatly helped by "blockchains". XMPP already does federated IM, since long before the current fad.
I match any vague handwaves about identity or security with vague handwaves at existing SSL certificate authorities, and an observation that if you're going to complain about the security of such things I get to apply an equal amount of effort towards breaking your blockchain solution, e.g., if you're going to complain about nationstates getting root certificates they shouldn't, I get to point out your tiny little blockchain for IMs is equally vulnerable, if not more so.
Thank you, great comment, excellent points.
I'm not discussing here nation-state certificate ledgers vs my small miserable blockchain, but instead an instance of a federated (say, XMPP) network server vs blockchain based solution. From my point of view, on this level, it provides more security and, what is more important , incentives to run such a thing.
A blockchain-based solution to what, though? Bearing in mind the XMPP network exists now, and works. (It may not be "winning", but it works.) What is even the problem?
Though I will concede your point slightly; if XMPP needs some more Hype Juice to win, I can't deny "but on a blockchain!" could help there. Kinda not being sarcastic here.
I don't think there are any 3 that are exactly what you ask about ("chat-on-blockchain thing").
However, from my understanding of Telegram's ICO and "leaked" roadmap, they appear to be doing a decentralized chat the may leverage their own blockchain for some features (identity, tokens etc.).
I think Status.im is another example, but it's currently early access I believe.
My own product, stealthy.im could be another example. The web product is in production. It builds upon blockstack, storing identity and storage pointers in the blockchain.
So that's 3. I could probably list a few more, but again they wouldn't strictly satisfy your precise criteria in one or major ways. I think @jerf's response is really good--for us the "why" of blockchain is in identity and providing a verifiable decentralized storage network through blockstack. The underlying bitcoin blockchain wouldn't be suitable for message storage or sdp handshaking due to latency as another person pointed out.
Thank you for providing an example. It's not a "bunch" but still. Could you explain why did you use word "regrettably", is it a bad thing these projects exists?
I think @detaro says 'regrettably' because of the distaste many have about ICOs and the hype related to them. However, I too would like to hear from @detaro on this.
Pretty much, yeah: pushing actual messaging over a blockchain is just horribly inefficient and I don't see it being a workable idea, so it seems dishonest to me to widely promote it and collect money for it.
Other related things are fine: e.g. mapping public keys to human-readable identifiers like a nickname is a good match to what a blockchain is good at, I get why people like the idea of cryptocoin-payments in a messenger platform, ... Still leaves the general concern of "does this really need it's own coin with an ICO and hype", but at least the ideas make some sense there.
There are several projects for that of course. ZenCash is one of them. I run 5 ZenCash masternodes, so it works, but it's a resource hog and it's really not fast.
What would be the point anyway? A dedicated peer-to-peer messaging network that doesn't need to keep track of the entire history of everything seems much more appropriate. IRC comes close to that with its federated architecture, although I suppose a completely seemless bittorent-like peer-to-peer chat using public key cryptography for message authentication could be pretty great.