Short answers, pulled from the story.
The US National Academies Press must disseminate works as widely as possible while remaining financially self-sustaining through sales. This dual goal has driven decades of experimentation with online publishing models.
In 1993, the entity known as the National Academy Press became the first self-sustaining publisher to make material available on the Web for free. By 1997, one thousand reports were accessible as sequential page images starting with i, then ii, then iii, and continuing onward.
By early 2025, twenty-five million PDFs had been downloaded since all reports became accessible without charge. The NAP announced it would provide full text of all reports from the National Academies of Sciences, Engineering, and Medicine as free PDF downloads on the 2nd of June 2011.
Michael Jon Jensen served as director of publishing technologies from 1998 through 2008. He contributed to discussions about free distribution in environments of content abundance during his tenure.
The conclusion showed that 42% of customers would take the free PDF when interrupted during print book purchases. This meant 58% of potential purchasers remained willing to pay for printed copies.