What is Facebook Open Graph?
Open Graph is the way that Facebook organizes the information and connections on its platform. It is an extension of Facebook’s social graph that anyone can build upon, whether by adding simple a Like button to a website or developing full-scale integrations like Spotify’s music service.
When Facebook began, users could only connect with other users. With the introduction of the Open Graph protocol in 2010, users became able to connect with objects on Facebook and around the web by clicking Like. By adding a bit of code to their sites, publishers could turn any webpage into a Facebook object. That means the page becomes indexed in Facebook search and gets added to user’s profiles.