To keep a platform viable it is important to have a vibrant ecosystem with complementors releasing a variety of products that work on the platform. With iGoogle (is Apple OK with this? :-)), Desktop and Gadgets, Google allows users to access that are developed by third parties. According to this
site, Google has over 4800 gadgets available to users. In order to keep this network of complementors growing, Google has started
Google Gadget Ventures to financially support development of popular gadgets receiving over 250,000 page views a week (that makes
9% of them eligible for funding). This funding should act as both a quality control and growth mechanism for Google's platform. Google's product APIs support the ecosystem by providing toolkits and forums to developers.
www.programmableweb.com has recently started
tracking this and other platform vendors separately.