Amazon just dropped prices on its popular Amazon S3 API, which provides storage to much of the web. The service will pass 1 trillion objects stored this year. With that volume comes opportunities to lower the costs, as we've seen from other companies whose entire product line includes APIs.
Trading systems have historically been the province within large financial institutions that as “master of the universe” controlled trillions of dollars in equity. They did this by essentially locking up access to transaction engines and applications that enable most of the trading that takes place on Wall Street and other exchanges across the globe.