From their site: You build great web applications. We have millions of users who store their data on Yahoo!. Browser-Based Authentication (BBAuth) makes it possible for your applications to use that data (with their permission). BBAuth also offers a Single Sign-On (SSO) facility so that existing Yahoo! users can use your services without having to complete yet another registration process. The first time a user visits your web site, you redirect them to a specially constructed Yahoo! URL where they can login and grant your application permission.
The following is a list of libraries from ProgrammableWeb's Library Directory that matched your search term. Although there many different interpretations of the word "library" among software developers, ProgrammableWeb adheres to a specific definition so as to clearly distinguish libraries from SDKs and frameworks in a way that will facilitate clean search results. In ProgrammableWeb's parlance, the term "library" is strictly used to describe a platform-specific software tool that, when installed, results in the provisioning a specific API. Conversely, SDKs are exclusively for consuming APIs and Frameworks are agnostic to specific APIs. If you think a library, SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.