To answer your question on what it does : cjdns is a routing protocol that intends to replace the current IP protocol. Like the standard IP protocol, it needs a way to communicate with another node to function (the default gateway). From there, you can communicate with the rest of the network. Your packets will go to the default gateway, who will then redirect it to the "closest node" recursively, until it reaches its destination.
You can setup cjdns over the current internet (essentially making cjdns an "overlay network" like tor) using UDP, or through an ethernet link.[1]
CJDNS indeed works in a mesh : anyone can route other people's traffic, somewhat similarely to tor. The only difference is that you need to manually configure your "Entry Node" (to lift tor terms). See [0] for the reasoning.
About the name, the creator is Caleb James DeLisle, so I guess CJDNS stands for Caleb James DeLisle's NameServer ? Doesn't really make much sense but I don't see how bad a thing it is.
[0]: https://github.com/cjdelisle/cjdns#2-find-a-friend [1]: https://github.com/cjdelisle/cjdns/blob/master/doc/configure...
"Where did the name cjdns come from?
Cjdns was based on a codebase which was originally intended to handle name resolution (DNS) and so it was a combination of 'cjd' and 'dns'. The project changed direction early on and currently is still lacking DNS resolution but the name stuck. Make up your own acronym for it if you like."
Source: https://github.com/SlashRoot/cjdns
What is it? The author has said it is meant to be a single binary: a router. The router accepts "customized" IPv6 addresses, e.g., each address contains a public key fingerprint. The packets are also custom, each containing a full route to the destination, which might be reminiscent of the bang path in UUCP. The nodejs stuff is just a prototype method of getting data from the router.
I remember watching a video of him explaining this at a cafe a number of years ago. Not sure if that was the first "public announcement". In that video he mentions a concern over censorship via DNS. And then he states that at a certain point he realized routing was easier to do than DNS.
http://www.youtube.com/watch?v=zINQYkl01N8
He uses NaCl. As for the name "cjdns" and why he started out experimenting with DNS, my guess was always that the original experimentation he did with NaCl was probably related to encrypting and forwarding DNS packets (or perhaps custom "name system" packets), since encrypting DNS packets was the "PoC" for NaCl.
Should it be read as CJ DNS, i.e. something to do with DNS? Or CJD (author's initials) NS (??? again, name server?)? C (?) J (JavaScript/Node) DNS?
Related, what the hell it is, actually? You say in other comment that it's a mesh network, they say it's a network, but I see a program to install. How a program is a network? What does it do?