The facebook-node-sdk by amachang allows developers to implement Facebook API functions using Node.js. It supports the Facebook Graph API, Facebook Query Language (FQL), and REST API. This SDK is compatible with Facebook's official PHP SDK.
The Votizen API aims to get friends to involve their friends in supporting candidates. The API website notes that the API is entirely based on HTTP. Votizen is based on the premise that, "Voters are more likely to listen to friends than campaign volunteers." Votizen is the first "social campaigning platform built entirely on personal connections."
Shoutlet, enterprise social marketing platform, has added a contact form API to its plethora of social media services. The API allows developers to gather contact information (e.g. data from an online sign up form) and automatically update the Shoutlet contact database with the pertinent information.