No internet, no email......... Period.
No internet? Make our own. Wireless hop it.
Need a plan for numbering, 10.lat.long.station, and a plan for dns.
Stations can give out other private addresses, allowing many users.
Some other complications, routing, but it could be done. Not that many will use it to start, but heck, it would be there - with no real central control.
Online Pool Games, play for free - It's my own site.