via Abstruse Goose
SETI astronomers are always looking for signs of extraterrestrial life by watching the skies for radio signals (sadly, with the exception of the Wow! Signal, there hasn't been any promising signs), but can the reverse also be true? Are alien civilizations out there watching for signals from Earth - and if so, what sort of things are we telling them through our television broadcast.
In Carl Sagan's 1985 novel Contact, which was later turned into a Hollywood blockbuster, alien's first transmission to Earth contained images of Adolf Hitler (uh-oh!) opening the 1936 Olympic Games in Berlin. Obviously, they've been watching our TV. But if you think watching Hitler was bad, imagine getting transmissions of Jersey Shore, which has just now reached Alpha Centauri. Needless to say, we are all doomed!
Abstruse Goose has an updated 2014 version of a visualized list of what TV shows aliens are now watching - given the electromagnetic broadcast that leaked into space.