open graph

    og:title - The title of your object as it should appear within the graph, e.g., "The Rock".
    og:type - The type of your object, e.g., "video.movie". Depending on the type you specify, other properties may also be required.
    og:image - An image URL which should represent your object within the graph.
    og:url - The canonical URL of your object that will be used as its permanent ID in the graph, e.g., "http://www.imdb.com/title/tt0117500/".