Apps that link to your content can then use this metadata to deep-link into your app, take users to an app store to download the app, or take them directly to the web to view the content.
Allows a website to define how a page is rendered in Internet Explorer 8, allowing a website to decide to use IE7 style rendering over IE8 rendering.
Content Security Policy is best used as defense-in-depth, to reduce the harm caused by content injection attacks.
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
Open graph title entity tag
Indicates that the site provides an interface specifically for searching the document and its related resources.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".