Structured data has an open platform, thanks to a new startup aptly named Factual. At first glance, it seems like Excel on the web. However, Factual is more database-oriented, with joining and filtering built-in. Plus, sharing and discussing the data is an integral part of the experience. Most functions on the site, including both reading and writing data, can also happen via the Factual API.
Here is an interview with Scoreoid founder and CEO, Almog Koren. Scoreoid allows you to gamify apps using the Scoreoid API and backend as a service. With 3000+ games and almost 1.8 billion monthly sessions- this is one API startup that seems to be going places.