AdSense is an ad serving application run by Google. Website owners can enroll in the program to enable text, image, and, more recently, video advertisements on their websites. These advertisements are administered by Google and generate revenue on either a per-click or per-impression basis. Google not only offers AdSense for ...
Google+ platform websites integration using the Google+ platform tag.
The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
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
Sites who has this tag are verfied by google to use WebMaster tools
By adding rel="home" to a hyperlink, a page indicates that the destination of that hyperlink is the homepage of the site in which the current page appears.