Pull data out through API?

Is there a set of API quidelines to get information out of WordPress and consume it in other ways? Such as Flickr has an API that lets you build a slideshow for your images. Or more like this: http://www.flickr.com/explore/clock/

Can you pull the data down and recompile that information? Like create a site where you can search all blogs for a word and present the information in a creative way? I am a Flash programmer that is interested in a mashup with WP.

Any help would be greatly appreciated.