What if you published ground-breaking research. Would anybody notice? How would you know they noticed? Such questions aren't just for the narcissistic mad scientists among us. What if you funded the research? You'd want to know the impact. Altmetric tracks "article level mentions". These metrics are defined by the Public Library of Science (PLOS) as measuring usage, citations, social bookmarking and activity, media coverage (including blogs), ratings and discussion activity. The Altmetric API provides access to its metrics that are derived from its database of over 300,000 articles and over 8,000 journals.
Before 1500, monks spent their lives copying the Bible by hand. That method was replaced by printing presses for the next 500 years. Today, ebooks are set to end the practice of pulping trees and smearing them with ink. In all this change the direction of information access has been constant for half a millennium: faster and faster, easier and easier. The next revolution for publishers is APIs for books.