ShareThis is the largest market for sharing and influence across the web, reaching more than 400 million users across nearly 1 million sites. ShareThis makes content more engaging for publishers and marketing more impactful for brands by tapping into its true influence and value. Based in Palo Alto, CA with offices in New York a...
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