Yesterday, Simon & Schuster notified libraries via their ebook distributors that they are switching over to a uniform two-year metered access license model as of August 1. Currently, their ebooks are offered via a one-year license, and their ebooks are offered via a perpetual license. In addition, they are also offering a new “per-checkout” model.
If you have not already read the notice, we encourage you to dive in at your earliest earliest convenience. Read the letter from Simon and Schuster.
EDIT: Adding a link to a related article in Publishers Weekly.