The most defining traits of pop music continue to change each year, leaving popularity, the concept from which the label is derived, as the only uniting principle between pop acts of today and yesterday. If there's any other distinguishing mark of pop music, it's that every generation's parents have deemed it the formal end of polite civilization as we know it. Funny then that as the years have passed, many of those so-called threats (such as the Beatles and Elvis) have turned out to be our most enduring artists.

If Elvis and the Beatles were the cornerstones of pop music throughout the '50s and '60s, the Who, Aerosmith, Steely Dan, and other similar bands were their '70s-era heir apparents. There's an entire sub-section of society that would argue in fact that REO Speedwagon, Styx, Journey, and Chicago were the real pop music breakouts of the '70s, but it all depends on who you were and what you were doing in that decade.

Pop Music in the '80s and Beyond

If debate remains about the true pop music stars of the "me" decade, there's less acrimonious campaigning for and against their '80s counterparts. Michael Jackson, Madonna, U2, and Bruce Springsteen all occupy well-entrenched spots throughout the Reagan era of pop. After that, however, things once again become muddy when the '90s usher in better indie rock and "grunge."

Nowadays, the music business has been so completely flipped on its head that the standards for measuring pop successes have been torn down. A band such as Radiohead may be heralded as the greatest act on earth by a wide swathe of the music-loving populace, only to turn around and sell one-twentieth of the albums sold by Britney Spears. Labels and categories being what they are, it's almost impossible to keep up with every current trend (how does one define rock music today? How about R&B?) in the current climate. That means it's even tougher to define the benchmarks of commercial success and, therefore, the real meaning of pop music.