Despite the advantages of the "new" technologies such as the Internet, satellites, Facebook, Ipods, etc., they can all be blocked and censored by countries who wish to do so -- and they frequently do so.
Shortwave radio, on the other hand, is the only medium of communication which can reach across borders -- and around the world -- without the need for permission from governmental authorities. Shortwave is the only medium of truly person-to-person international communication which cannot be stopped at national borders.
When crises occur in any country -- earthquakes, hurricanes, tsunamis, wars and political upheavals, to mention a few -- people rely on shortwave radio to transmit news and information.
And outside of times of crisis, listeners rely on shortwave stations to provide them with a wide variety of alternative programming that is not available on their local and national media.
Because it's short.
The shortest distance between two distant places.