The terms SW1 or SW2 dont have any particular meaning. Some radios will go from SW1 to SW9 but may not cover any more band than another radio with SW1 and SW2.
Some modern radios will tune continuously from 30kHz to 30MHz (or more to GHz). They can vary their bandwidth for receiving different types of signal and use various modes for detection.
There are many web sites devoted to
SWL.
Due to the ability to propogate over long distances short wave used to be the only way to get news from overseas (or news from home if you were an ex-pat) .
In the tropics, short waves are still favoured, over broadcast band, due to electric storms.
With modern technology and developements Short Wave Listening comes under the hooby of international or long range (DX) reception. It includes TV as well as voice and other more exotic modes.
DRM is a mode being tried out by some international broadcasters which can give near FM quality over SW.
Satelites have made programme distribution much easier and broadcasters can have local relays in or near their target countries - thats why its possible to get good reception of BBC World Service in places far from London. China Radio International can be easily received in europe courtesy of Albania. Some International broadcasters even use local relays on FM.
WRN distributes International radio services world wide.
VOA operated TV Marti which broadcast to cuba using a tethered ballooon to support aerials 16km (10m) high above Cudjoe Key, Florida. (The aerostats were blown away by a hurricane)