Putting an end to download-and-go: The website's role in a content marketing ecosystem - Wilcock - 2017 - Learned Publishing - Wiley Online Library

"If publishers are to thrive in an increasingly hostile landscape of open access mandates, decreasing research and library funding, ResearchGate, Sci-Hub and other pirate sites, and out-of-copyright usage, all while defending against everyday competitive pressures, they must distinguish their content and their brand from their competitors’ and deepen their relationships with readers and subscribers. However, quality content is no longer enough to attract and retain online readers, who can too often find a publisher's paywall-protected content on another site where it is available for free or request it from colleagues.

For example, a study by the inventors of Unpaywall, a browser extension that locates (legally) free versions of articles, found that ~4.8% of all journal articles with DOIs – ~2.97 million articles – are behind a paywall on their publisher's site but have also been deposited in open access repositories by their authors; such articles account for over 9% of all searches via Unpaywall (Piowar et al., 2017). As of August 2017, Unpaywall had about 80,000 users (Chawla, 2017)...."