The Beatles were an English rock band, formed in Liverpool in 1960. With members John Lennon, Paul McCartney, George Harrison and Ringo Starr, they became widely regarded as the foremost and most influential act of the rock era. In the early 1960s, their enormous popularity first emerged as "Beatlemania", but as the group's music grew in sophistication, led by primary songwriters Lennon and McCartney, the band were integral to pop music's evolution into an art form and to the development of the counterculture of the 1960s. Their continued commercial and critical success assisted many cultural movements--including a shift from American artists' global dominance of rock and roll to British acts (British Invasion), the proliferation of young musicians in the 1960s who formed new bands, the album as the dominant form of record consumption over singles, the term "Beatlesque" used to describe similar-sounding artists, and several fashion trends.

The Beatles' impact on the US was particularly strong, where a garage rock phenomenon had already begun, with hits such as "Louie Louie" by the Kingsmen. The movement received a major lift following the group's historic appearance on The Ed Sullivan Show watched by a record-breaking viewing audience of a nation mourning the recent death of President John F. Kennedy. Bill Dean writes: "It's impossible to say just how many of America's young people began playing guitars and forming bands in the wake of The Beatles' appearance on the Sullivan show. But the anecdotal evidence suggests thousands - if not hundreds of thousands or even more - young musicians across the country formed bands and proceeded to play." Tom Petty, who played in two garage bands in Gainesville, Florida during the 1960s, is quoted mentioning the Beatles' appearance on The Ed Sullivan Show and how it influenced him to be in a band. According to him: "Within weeks of that, you could drive through literally any neighborhood in Gainesville and you would hear the strains of garage bands playing ... I mean everywhere. And I'd say by a year from that time, Gainesville probably had 50 bands." For many, particularly young baby boomers, the Beatles' visit reignited the sense of excitement and possibility that had been momentarily taken by Kennedy's assassination. Much of this new excitement would be expressed in music, sometimes much to the chagrin of parents and elders, as kids raced to start bands by thousands, and this proliferation of new groups was not limited to the United States. While the Beatles are often credited for sparking a musical revolution, research conducted by the Queen Mary University of London and Imperial College London suggests that the changes sparked by the band were already developing long before they entered the US. The study, which looks at shifts in chord progressions, beats, lyrics and vocals, shows that American music in the beginning of the 1960s was already moving away from mellow sounds like doo-wop and into more energetic rock styles. Professor Armand Lero argues that the Beatles' innovations have been overstated by music historians: "They didn't make a revolution or spark a revolution, they joined one. The trend is already emerging and they rode that wave, which accounts for their incredible success." Beatles biographer Mark Lewisohn disagreed with the research by Queen Mary University, saying it "[doesn't] stack up ... Speak to anyone who was a young person in the US when The Beatles arrived and they will tell you how much of a revolution it was. They were there and they will tell you that the Beatles revolutionised everything."

Using a quote from the above article, answer the following question: What impact did they have?
many of America's young people began playing guitars and forming bands in the wake of The Beatles' appearance on the Sullivan show.