Alongside the exciting release of Google Sidewiki today, we're also happy to announce the availability of the first version of the Google Sidewiki Data API. Google Sidewiki is a new feature of Google Toolbar (for Firefox and Internet Explorer) that lets everyone contribute helpful information next to any webpage. Our post over on the Google Blog goes into more detail and also has a video that shows Sidewiki in action. To start using it yourself, go to google.com/sidewiki and install Google Toolbar with Sidewiki.
On the developer side, we're releasing a Google Sidewiki Data API today that lets you work freely with the content that's created in Google Sidewiki. You can use it to retrieve all entries written about a particular webpage as well as all entries written by a given Sidewiki author.
So after you've played with Sidewiki in the browser, give it a whirl in your console too -- we have client libraries, documentation and code samples ready to go for you. We'll be excited to see what gadgets, projects and extensions you'll think of. A translation gadget that displays and translates Sidewiki entries on the fly? A Google App Engine-powered browser of all Sidewiki entries? Your own browser extension or Greasemonkey script?
The Google Sidewiki API is available in Google Code Labs and is read-only at the moment. We've set up a developer-oriented discussion group and issue tracker where you can discuss your experiences with the API and where we'd love to hear about your feedback and projects. Keep us posted!