hotline is a file client/server programme i.e someone needs to run a server and everyone including the server operator run the client. The clients connect to the server and this allows resume-able file transfer either way (of course the server operator has control over this); it allows chat and private messaging between any of the clients. It also provides for newsgroup posting for delayed correspondence. It is very useful for community based activities, eg techno-heads (in my case - but any other activity as well )communicating and sharing their... ahhhm stuff.
It was originally a Macintosh programme but has been ported to the PC , so has a slight non-Windows look and feel to it. It is FREE (altho you can pay for getting rid of the ads it has) Get it from Tucows
There are various methods for finding Hotline servers. Trackers are used within the Hotline programme itself and there are some web-sites that list HL servers and allow searches on them for subject material.