There are telephone conferencing facilities where people call
in to a central location. The central location fields all calls,
and joins them in a conference. There are some security features,
such as a conference ID and password.
Some broadband providers, often notably cable, have non-server
provisions in their TOS. Of course one can firewall out their
scanner, but that's hardly ethical. Even if the TOS are stupid,
for some of us, that's our only path to broadband.
Is there a place where two parties can both connect, and be
connected to each other, as if one party had been running a
server? (SSH connection, probably.)