Well, with Winlink you can send emails to/from anywhere on the planet - I once sent an email via an RF relay in California (I'm in Vancouver, Canada). It could have been anywhere in NA though. Pretty sweet. There's a Winlink Wednesday "net" where people "check in" by sending a check-in winlink mail via RF to the net controller (organizer) who collects all the submissions and shares logs of all the participants. This is just one example. There's other neat weak-signal stuff like FT8/FT4 and JS8call, with which I've made contacts of ~13,000km with 5 watts of power for example.