At the heart of YOS are a set of complementary platforms that allow developers to rapidly access Yahoo! network data and develop applications, with access controlled using an open authentication standard.
While the Yahoo! Applications Platform provides the channel for extending your apps across the Yahoo! network, the Yahoo! Social Platform provides the social data that can connect your users and drive engagement to your app across the Internet. This social data can be used not only on the Yahoo! network through YAP, but it can also be used off-network as data for your socially aware applications. The Yahoo! Social Platform lets you tap into the social data of millions of users on and off the Yahoo! network. Incorporate Yahoo! social data into your applications via an easy-to-use, resource-oriented Web service API. For more information about the Yahoo! Social Platform, refer to the front page of the Yahoo! Social Platform.
Yahoo! makes a lot of structured data available to developers, primarily through its Web services, but also CSV documents and RSS feeds. The Yahoo! Query Language (YQL) service is a single endpoint that allows developers to query, filter, and combine data across Yahoo!, as well as external sources such as RSS feeds or HTML pages. YQL exposes a SQL-like SELECT syntax that is both familiar to developers and expressive enough for getting the right data. Through the SHOW and DESC commands we enable developers to discover the available data sources and structure without opening another web browser. For more information about YQL, refer to the Yahoo! Query Language documentation.
Access to all data available through YOS APIs is securely provisioned using OAuth, an open, public, and standard model of authentication that doesn't require your user to divulge their passwords. Instead, you tell Yahoo! what types of data you need to access and we in turn ask your users if it is OK for you to access that data. If your users say yes, you'll be given a token that carries in it the permissions to access specifically the information you're authorized to access and nothing more. Several companies already use OAuth, and there are several open libraries that can help you implement OAuth on your site or application. For more information on using OAuth to access YOS, refer to the Yahoo! OAuth Quick Start Guide.