Are Smart Phones Spreading Faster than Any Technology in Human History?

New digital technologies tend, as a rule, to achieve mass marked adoption faster than older analog technologies. That seems to hold true for smart phones and tablets, for example. 


It took landline telephones about 45 years to get from 5 percent to 50 percent penetration among U.S. households, and mobile phones took around seven years to reach a similar proportion of consumers. 


Smart phones have gone from five percent to 40 percent in about four years, despite a recession.  Over time, successful new technologies get adopted faster, every decade. 


Here's another visualization.