Involver launched its Engagement Optimization API last week (read the official release here). Partners are utilizing the API to "optimize their ad spend on social in the way they've been doing across the web for a long time." Although advertising across social networks has been deployed for quite some time, advertisers have had limited tools to track engagement. Facebook Insights is probably most commonly used to analyze social data. When users have required deeper analysis, the advertisers were forced to use highly custom integrations.
Keek, social video network, recently announced the release of the Keek API. Alongside the API launch, Keek established a developer portal that includes tools and resources to assist developers in integrating Keek with third party applications. The Keek API grants developers access to public keeks (i.e. 36 second video updates), search, user profiles, klusters, and more.