Floodlight is an optional feature in DFA that allows advertisers to capture and report on the actions of users who visit their website after viewing or clicking on one of the advertiser's ads. For the implementation of Floodlight, Floodlight tags must be placed on the advertiser's webpages.
A family of standard web feed formats used to publish frequently updated information like blog entries, news headlines, audio and video.
A pingback is one of four types of linkback methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking to, or referring to their articles.
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
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".