I'm going to assume we're talking U.S. culture here, so I'll be referencing only the U.S. The Beats were known in popular culture and to the public but misunderstood (much like hippies later) because they were often depicted through the filter of more mainstream perspectives. Norman Mailer wrote a popular essay (entitled "The White Negro") about them and how they, from his perspective, sought to emulate Black jazz musicians of the era by adopting a bohemian lifestyle and outside status. Early on, they were also depicted as potentially dangerous --Joseph McCarthy identified the beat movement as Communist and a threat to national security. J. Edgar Hoover referred to "communists, beatniks, and eggheads" as the three most dangerous groups in America. As they became more familiar to mainstream culture, however, they became more of a fashion icon (the beret and goatee and black outfits) and a punchline. Take, for example, the series The Many Loves of Dobie Gillis, in which Doby's friend Maynard G. Krebs (played by Bob Denver) is portrayed as a "beatnik." He was a caricature and held up as a joke--but that was in the early to mid 60s, after the beat movement had been around for almost 20 years. The more prominent people in the movement, such as Kerouac, received publicity in Life Magazine. Life also contributed to the polarized public view of the Beats.

Sources:

Miller, Douglas T. and Marion Nowak. The Fifties: The Way We Really Were, Doubleday & Company, Inc., 1977.

Watson, Steven. The Birth of the Beat Generation: Visionaries, Rebels, and Hipsters, 1944-1960, Pantheon, 1995.