The Diigo Objective-C SDK by Taichiro Yoshida allows API interaction to implement bookmarks into web applications. With the SDK, developers can sync bookmarks, display bookmarks in a menu, and open bookmarks in browser-based services.
Online bookseller Erapublications has an API for its in2Era web service for selling ebooks through online distributors. According to its documentation, this RESTful API, which requires an authentication key, integrates its catalog onto your site. Distributors get a cut of the sales.
A learning management system (LMS) is a way to track, report, document and deliver online educational resources. The Tin Can API, provided by SCORM, is attempting to rethink the way that LMSs receive and catalogue information.