Now, with the Internet, we can simply watch trailers of a film on YouTube or other sites. But how did people watch trailers before all this was created? Were trailers shown in the cinemas only?
Where did people watch movie trailers? Before the internet, there were movie theaters, broadcast TV, and cable TV. Before cable TV there were movie theaters and broadcast TV. Before broadcast TV there were movie theaters. Before movie theaters there was no place to watch trailers that were not made to advertise movies that were not made.