The press release was issued yesterday. SS has partnered with Optimizely and Sprinklr

http://www.prnewswire.com/news-releases/shutterstock-expands-successful-api-program-with-new-technology-partners-300207701.html

Shutterstock's developer page on this program lists Facebook (old news) plus others such as Percolate and NewsCred.

NewsCred and the new partner Sprinklr seem to be doing something similar. The NewsCred Image Editor may have something to do with the SS image editor development? Another article on what NewsCred does. Here's SS's post about the Percolate partnership

The interesting thing is that this appears to be a different route to integrating into customer's workflow. Adobe is plugging stock into their creative tools. SS is plugging it into online platforms and apps where the ads (or other content) are created or tested.

Perhaps SS's bet is that more and more use of imagery and video will be by people using web tools to do their marketing or customer engagement activities. I would assume Photoshop and Illustrator aren't much in evidence in these environments. From SS's developer page:

"WHY CONSIDER A PRODUCT INTEGRATION?
Create a seamless workflow for users to find images or video while staying on your platform"

It'd be interesting to know how contributors are compensated for images used in A/B testing or any of the above sites' activities, but I assume it fits into one of the existing packages. But the more interesting thing (I think) will be to watch how (if) this list of partners grows and what (if anything) that means for the other big players.