OK, this goes from DNS, to email, to... something which is not Usenet, which surprised me, because Usenet fulfills most of the goals of being a social network much better than either DNS or email can.
Usenet can, in fact, be built on top of an email delivery mechanism, such as UUCP, which is the store-and-forward dial-up network both Usenet and Unix email ran on top of before Unix was allowed to sit at the big-kids table of networking (Arpanet). We have NNTP now, of course, and a number of NNTP servers you can run on a laptop because it somehow fails to be 1995 anymore and most of the people reading this have better network connections and more disk space than most of the servers which ran NNTP in the heyday of Usenet.
Usenet can, in fact, be built on top of an email delivery mechanism, such as UUCP, which is the store-and-forward dial-up network both Usenet and Unix email ran on top of before Unix was allowed to sit at the big-kids table of networking (Arpanet). We have NNTP now, of course, and a number of NNTP servers you can run on a laptop because it somehow fails to be 1995 anymore and most of the people reading this have better network connections and more disk space than most of the servers which ran NNTP in the heyday of Usenet.