@lsn
ZeroNet had a major flaw in that it required a certificate to post anything. This is fine for sites like blogs, forums, or wikis, but for anonymous sites like pastebins or imageboards, it doesn't work so well. There was an 8chan bunker on ZeroNet when the original site went down. They had some hack solution that automatically generated and rotated keys to maintain some level of anonymity. It didn't work out and journalists also exposed that many users on said bunker were using the site with their bare IP, which was another problem as ZeroNet was not anonymous on it's own. All that on top of the fact that you seed an entire website, including any illegal content that someone may have upload made people lose faith in the project. The lead developer seemed to have stopped working on it around the same time as the failed 8chan bunker incident.
As for OpenNIC, I feel like the thing that is holding it back right now is that it doesn't address VPN, proxy, and Tor users, as you are using their DNS servers instead of your own, so unless your VPN server is using an OpenNIC DNS server, then it won't be able to connect to an OpenNIC site. It also doesn't address something like emailing from a server with an ICANN domain to a server with an OpenNIC domain as the ICANN email server needs to be connected to an OpenNIC server in order to recognize it.