Presented below is the U.S. market penetration achieved by nine technologies since 1876, the year Alexander Graham Bell patented the telephone. Penetration rates have been organized to show three phases of a technology's spread: traction, maturity, and saturation.
Those technologies with "last mile" problems—bringing electricity cables or telephone wire to individual homes—appear to spread more slowly. It took almost a century for landline phones to reach saturation, or the point at which new demand falls off. Mobile phones, by contrast, achieved saturation in just 20 years. Smart phones are on track to halve that rate yet again, and tablets could move still faster, setting consecutive records for speed to market saturation in the United States.