Google+ platform websites integration using the Google+ platform tag.
Let visitors recommend your content on Google Search and share it on Google+.
This script is the defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer.
Open graph description entity tag
Any offered product or service. For example: a pair of shoes; a concert ticket; the rental of a car; a haircut; or an episode of a TV show streamed online.
An offer to transfer some rights to an item or to provide a service—for example, an offer to sell tickets to an event, to rent the DVD of a movie, to stream a TV show over the internet, to repair a motorcycle, or to loan a book.
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