A half-century ago, in June 1975, Jaws swam into cinemas, gave audiences a good scare, and rewrote movie history.

The shark thriller became the first summer blockbuster with a playbook that Hollywood studios still follow today. Jaws was heavily marketed, creating buzz that positioned the film as a must-see event.

A recent test screening report appeared to spoil the identity of the actor who will play Jor-El in Superman, and lead star ...