Why the nickname?
For many years during the Cold War (1947-91), these regions received only local television stations and couldn’t pick up stations from West Germany (though a few West German radio stations were accessible). This resulted in the populations of former East and West Germany being exposed to vastly different television programs and news, which is believed to have cultivated a difference in individualistic development, communal feeling, and lifestyle choices.
West German television was generally considered to be superior and have more reliable news coverage, and thus, the populations in parts of former East Germany that had no access to this were mocked for being out of sync with the latest West German and world news. This earned the region the satirical nickname of Tal der Ahnungslosen (“Valley of the Clueless”).
The later years
Starting in the late 1970s, as cable and, later, satellite television became increasingly available, more and more people (even those residing far from the former East-West border) gained access to West German television. Within a few years, the number of people with zero access to even one West German television station was negligible.