The goal of the Google Data APIs is to give developers a consistent (and familiar) way to integrate with Google products. At their heart is Atom and the Atom Publishing Protocol, and we've created extensions on top of those open standards to add features like specifying a calendar schema or authentication protocol.

We've always intended for the Google Data APIs to be open and reusable, and today we've taken an extra step to make that intention clearer. We're giving a no-charge, royalty-free license to any patents we have that you would need to implement Atom, AtomPub, or any of our extensions. The official way to do this was via an intellectual property disclosure to the IETF and the patent license now linked from the Google Data APIs docs.

We hope this will encourage sites who want to expose APIs for things like photos, videos, calendar, or contacts to reuse our schemas where they can, rather than reinventing the wheel. Doing so will make it easier for developers who are integrating with multiple sites or porting over an existing app to a new site.

To learn more, check out the Google Data APIs Blog or dive into the patent license itself. Also, be sure to register for the Google I/O conference. I'll be giving a talk there about Google Data APIs, and there will be opportunities for deeper discussions and direct interaction with the engineering team.