Microsoft is one of the first--and certainly the largest of--customers of Wolfram Alpha's commercial API (our Wolfram|Alpha API profile). For math and nutritional searches, Microsoft's Bing now uses Wolfram results.
Something new sprang up in the Flickr App Garden last month: "This is my Cam!" by Chris Martin (the San Francisco-based hacker, not that guy from Coldplay). Inspired by music sharing site This Is My Jam and built during Photo Hack Day 3, "This is my Cam!" uses the Flickr API to catalog the different cameras that were used to capture a particular user's photos.