Google will accept publishers of a variety of websites into the , including online retailers, blogs and book publishers.
It's common for online retailers to have affiliate programs. However, some U.S. states have recently passed laws that force e-tailers to collect sales taxes from shoppers who buy through online affiliates. In response, Amazon and Overstock have terminated their affiliate relationships with vendors in some states.
Google started doing a limited test of its program back in December.
"Starting today, we invite all interested site owners to apply to join the expanded Google eBooks affiliate program. Participating sites gain new revenue streams by giving their book-reading audiences an easy way to buy Google eBooks," wrote Pratip Banerji, product manager at the Google Books team, .
Google's eBookstore has about 3 million free titles and hundreds of thousands for sale. Participating publishers can hook up their sites to the program's main product feed, which gives them access to all books for sale. They can also customize the pool of books available to their site by working with .
Google has made eBooks accessible from desktop and mobile browsers and through applications, as well as compatible with a variety of e-book reader devices.
The eBooks service and store can be accessed from applications for the Chrome browser and for Apple iOS and Android devices. About 2.5 million eBooks applications have been installed so far.
With the launch of the affiliates program, Google continues its push into the digital books market, despite a major legal setback that has kept millions of books out its online store.
In March, Judge Denny Chin from the U.S. District Court for the Southern District of New York copyright infringement lawsuits from authors and publishers.
The settlement proposal drafted by Google and the plaintiffs -- the Authors Guild and the Association of American Publishers -- would have given Google broad access to sell millions of books it has digitized from university collections but without permission from copyright owners.
Google and the plaintiffs are still weighing their options in light of the judge's decision. They could decide to move ahead with the case and battle in court, or they could come up with another settlement proposal.
In the meantime, Google continues beefing up its eBooks program to better compete against rival digital bookstores from Amazon, Barnes & Noble and Apple.