Facebook Graph API
Definition - What does Facebook Graph API mean?
Google retired Social Graph API in April of 2012.
Techopedia explains Facebook Graph API
A key part of the Facebook Graph API is a list of tags for different object attributes. By using these provided standards, developers can ensure that their changes match the conventional syntax commonly used for Facebook pages and objects. For example, the API can include a tag like name or user identifying a specific party, or numeric tags for Likes and other quantifiable activities, to keep track of how many of these functions have been applied to a given Facebook entity.
The Social Graph API is an automated way for Web pages to declare social connections between themselves. For example, many websites link out to their own Twitter page. Behind the scenes, the link is done in a way that allows developers of social products know that there’s a social connection between the two.