The Open Graph Protocol is a snippet controller when adding your url to social media. It basically terms your page into a rich object that can then be used on Facebook.
The Open Graph Protocol is RDFa-formatted metadata that can be added to the head of your page html which controls the snippet that is shown in Facebook when you 'like' a page or add a URL to your post feed.
The Basic Metadata includes -
og:title - Title of your Page or Object
og:type - Type of Object ie. video, image, webpage
og:image - Image URL to add to your description
og:url - Canonical URL of your object
og:description - A one or two sentence description
og: audio - A URL to an audio file
og:locale - Language and territory
og:video - A URL to a video file
There are other optional meta data, structured properties, arrays and object types that can be added and a list can be viewed on the official Open Graph Protocol Website.
Once setup on your page, you can then use the Facebook Developer Debugger to check how your Open Graph Snippet will look and will let you know any warnings that should be fixed, like image size being too small.
Facebook has a knowledge-base for developers when implementing Open Graph for API which is a completely different way of using the technology but another option for controlling your snippet information.
If you would like Open Graph added to your site, contact Business Catalyst SEO for more information.