Steady, strong growth is expected for open-access journals: Physics Today: Vol 70, No 5

"Publishers are trying to accommodate demand for OA while maintaining the subscription model. Last October, Springer Nature launched a content-sharing initiative to encourage 'reasonable' free sharing with nonsubscribers by authors of articles in the publisher’s 2300 journals, including Nature titles. Immediately upon publication, authors are provided shareable links to their papers, which can be viewed but not downloaded. The links can be posted anywhere, including the author’s website, article-sharing sites known as scholarly collaboration networks (SCNs), and social media. Notably, an earlier year-long pilot version of the shared links program involving 50 journals resulted in no loss of institutional sales for the subscription-based journals.