Before this, Adobe and Lexcycle were already working together on bringing support for PDF files and the EPUB standard to Stanza, which currently has over 1.3 million users.

OPML for eBooks

One way to think about this standard is as a kind of 'OPML for eBooks' - only instead of RSS feeds, OPDS features a catalog of eBooks, including optional links to book covers and short summaries. Instead of making users jump through all kinds of hoops, eBook applications could simply allow users to 'subscribe' to and search through these catalogs from within the application - and users could then download them right to their eBook readers without having to go to a browser or another application first.

In a perfect world, where every eBook vendor adopted this standard, users would be able to find and acquire books from any device, whether it be a Kindle, a Sony Reader, a Windows Mobile phone, or a Windows desktop. The Stanza reader, for example, already features support for various stores, and if Amazon adopted this standard, it could easily enable its users to access any other OPDS enabled store. The experience would probably not be as rich as on a dedicated app or website, but it would allow users to access eBooks from a wider range of vendors (which, of course, might not necessarily be in every vendor's interest).

Just a draft for now

The OPDS standard is currently in draft form, but the core elements of the standard are support for the EPUB standard and the Atom XML based catalog format. The exact specifications are available on the project's wiki, where you can also participate in the project.

In his post about this announcement, Adobe's Bill McCoy argues that he hopes that this standard will give consumers a seamless mechanism to get eBooks from various sources, with the ability to read the texts on multiple devices, "without lock-in to 'One Store to Rule Them All'" - which we take as a reference to Amazon's Kindle and Kindle Store (though thanks to this hack, reading ePub books on the Kindle has now become a bit easier).

McCoy also rightly argues that having a standard for eBook distribution and acquisition will allow vendors to reach more consumers across a wider range of platforms, which, in the end, can only be a good thing for the emerging eBook market.