When we think about the great consumer electronics technologies of our time, the cellular phone probably springs to mind. If we go farther back, perhaps we'd pick the color television or the digital camera. But none of those products were adopted as fast by the American people as the boom box.
That factoid is a sidenote in a 2011 paper that I stumbled on from the Journal of Management and Marketing Research. Author Tarique Hossain included data from the Consumer Electronics Manufacturing Association on the "observed penetration rate at the end of the 7th year" for all the technologies listed above. Hossain's data didn't include the starting years for these seven-year periods, but I'm assuming they mark the introduction of the boom box in the mid-1970s. That would mean that by the early 1980s, more than 60 percent of American households owned some kind of portable cassette player with speakers attached to it.
It's worth noting that all five of the fastest-adopted technologies were for the consumption of entertainment not communication or production of media.