The reason nobody's in the map is you'll have to export it and get them to download the files to your map. Without those files, players won't be able to access the map. I believe once you export your map, just upload your map files to MediaFire and compress the files into a zip folder. Once that is done, merely copy the link and pass it out to your friends so they'll be able to download it.
I'm no experienced map maker, but I hope this helps in some way. If not, then I give my apologies for posting something already known to you.
As stated by Vespian, the reason why your other map had users in it was because they downloaded your map. So, if you want people to be in this map as well, export the map and put all the files into a .zip file. Then, you can upload them here. {Mediafire (http://mediafire.com)} Maps that you make are not like Bonfire, Lonely Cave, Ficho, etc. and can only be visible to those who have downloaded it. Good luck. c;
+Floof for Vespian for being helpful around the forums.