The publishers are McGraw-Hill, Pearson, and Houghton Mifflin Harcourt (part of Reed Elsevier) -- three of the five major global educational publishers (along with Cengage Learning and John Wiley & Sons).  These publishers are among the largest institutional image licensees. 

As we mentioned in our 2007 year-end review, PLUS is a pragmatic standard that solves a problem that has long plagued the stock image industry, that of standardizing rights licensing terms so that both image licensors (like stock image agencies) and licensees (like publishers or ad agencies) can make their image licensing processes more automated and efficient.  Standardization of licensing terms should also lead to a more economically efficient market for stock images, because licensees will be better able to make apples-to-apples comparisons of rights among licensors and to license only the rights they need.

Stock image agencies like Corbis and Getty Images might once have considered economic efficiencies like these to be harmful to their positions as market dominators.  But nowadays, they face increasing competition from free photo sites like Flickr, which only offer Creative Commons licensing terms and often end up being conduits for unintended commercial uses of high-quality imges. 

PLUS is on a positive, if deliberate, trajectory as it labors to keep its many constituents happy while developing its specs and its momentum.  It's close to our ideal of an open standard: pragmatic, focused, not over-engineered, and an economic win-win for all parties.