Before the advent of the internet, it was often difficult to determine if something was true or false. While those who firmly ensconce themselves in their Internet echo chambers can ignore the truth, reasonable people can use this tool to see for themselves if the latest rumor has any basis in fact.
In the 1960's, however, it was a lot harder to verify rumors. News traveled slowly and rumors often exploded before the targets of them had a chance to respond. That's why rumors of former mouseketeers and even Jerry Mathers dying in Vietnam were rampant.
In 1967, a rumor began floating around that Paul McCartney, star of the biggest band around had died in a car crash. Rumors such as these often spread far and wide back then and it was quickly shot down in a Beatles fan publication. Just a few years later, however, the story would explode into a worldwide conspiracy theory. Some Beatles fans went into a tizzy, looking for various clues in albums and films that pointed to Paul being dead, replaced by an imposter.
The so-called clues were found everywhere. Fans played Beatles records backwards and heard such phrases as "Paul is a dead man, miss him, miss him," "Paul is dead," and "I buried Paul". The album covers also carried clues. It was said that Abbey Road depicted a funeral- John in white was the preacher, Ringo was the undertaker, barefoot Paul was the corpse (it was said to be customary to bury bodies barefoot) and the denim clad George was the gravedigger.
Sgt. Peppers' iconic cover was reportedly a funeral for Paul, "attended" by people of whom he was a fan.
Even the innocuous cover of Let it Be allegedly held a clue- the only Beatle with a red background was Paul, symbolizing blood and death.
Even the films held clues; in this scene from Magical Mystery Tour, only Paul wears a black carnation which means he must have died.
So if Paul was dead, how was he still performing with the band? The theory was that he had been replaced because the British government was afraid that Paul's death would result in countless suicides from grief-stricken fans. The other three band mates went along with it but were conflicted, thus inserting these "clues" to secretly reveal the shocking news.
So what's the real story here? The most likely theory is that the so-called clues solely lived in the minds of the people who "found" them. Many of them are outlandish or based on false assumptions.
Another theory is that a few of the "clues" were actually placed there by the band as a practical joke to mock the 1966 rumors about Paul's death. John was known to be a prankster and possibly got a kick out of "killing" Paul, especially since their relationship was getting increasingly strained. Under this theory, the Beatles ended the prank because of Charles Manson. After Manson's crazy interpretations of their music led to grisly murders, the Beatles lost interest in their prank and never revealed it to the world.
We may never know the full truth about this strange time in Pop Culture history, but we can be reasonably certain that the stories about Paul McCartney's death are indeed a hoax.