[$] The NNCPNET email network

Running a modern mail server is a

complicated business. In part, this
complication is caused by the series of incrementally developed practices
designed to combat the huge flood of spam that dominates modern email
communication. An unfortunate side effect is that it prevents people from
running their own mail servers, concentrating people on a few big providers.

NNCPNET is a suite of software written by John Goerzen based on the

node-to-node copy (NNCP)
protocol that aims to make running one's own mail servers as easy as it once
was. While the default configurations communicates only with other
NNCPNET servers, there is a public relay that connects the system to the broader
internet mail ecosystem.