See what your Facebook friends have liked, shared, or commented on across the Web. This includes all variations of Like, Share and Follow Buttons, Embedded Posts, Comments, Activity Feed, Recommendations Feed, Recommendations Bar, Like Box and Facepile.
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.
The average rating based on multiple ratings or reviews.
A web page. Every web page is implicitly assumed to be declared to be of type WebPage, so the various properties about that webpage, such as breadcrumb may be used. We recommend explicit declaration if these properties are specified, but if they are found outside of an itemscope, they will be assumed to be about the page
Sites who has this tag are verfied by google to use WebMaster tools
The http-equiv attribute provides an HTTP header for the information/value of the content attribute. The http-equiv attribute can be used to simulate an HTTP response header.