Google has released a number of projects on sourceforge with its own google group for users to participate in, as well as some Open Source APIs from their new code.google.com page. There are 2 rss feeds (an update and featured programs) to keep up to date with changes on their page. This is an interesting turn from Google’s usual secretiveness. Perhaps they are trying to open up to the coding community which Amazon has been able to tap into. I would not be surprised if Yahoo! was quick to follow as well.
Particularly interesting are some of their APIs: Web Search to search Google, AdWords to interact directly with the AdWords Server, and Desktop Search to integrate into other applications and add new file formats.