Google's Books electronic bookstore now contains about 3 million free titles, up from 2 million when it was launched in December.
In addition, the roster of independent booksellers participating in the program has grown from about 100 to about 250, while the number of publishers has increased from about 5,000 to about 7,000, Google said.
The ebooks service and store, which are cloud-based, can be accessed from Google and partner websites, as well as from applications for the Chrome browser and Apple iOS and Android devices. About 2.5 million ebooks applications have been installed so far.
Of course, Google would have been able to announce a much larger number of available titles if its controversial proposal to settle copyright infringement claims with authors and publishers had been approved.
Unfortunately for Google, after a wait of more than a year, a US judge threw out the proposed settlement in March.
As hammered out by Google and the plaintiffs, the Authors Guild and the Association of American Publishers, the settlement would have given Google broad access to sell millions of books it has digitised from university collections but without permission from copyright owners.
Google is still weighing its options with regards to the copyright litigation. Whether another settlement is proposed or the case proceeds, it's clear that Google's relationship with authors and publishers in general could use some improvement.
Still, even with the recent legal setback, Google's eBooks service is considered a credible alternative to other digital bookstores from competitors like Amazon, Barnes & Noble and Apple.
Google is betting the success of its program on what it considers a more open approach than its rivals, making it as broadly accessible as possible from desktop and mobile browsers and through applications, as well as compatible with a variety of ebook reader devices.