The Wall Street Journal wrote about 50 Million Users: The Making of an ‘Angry Birds’ Internet Meme "Last week, we described a 100-page report on innovation and jobs written by two Oxford University economists that cited an eye-catching metric: It took 75 years for telephones to reach 50 million users, while the app “Angry Birds” hit that goal in 35 days. An accompanying chart showed radio took 38 years and TV 13 years. The numbers looked precise enough to appear like they were thoroughly researched."
They go on to site the origins of the meme and to look at the data. As I was reading it I kept wondering about the population size when the Internet started compared to the telephone. Thankfully they included these graphs: