The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
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.
The Platform for Privacy Preferences Project (P3P) enables Websites to express their privacy practices in a standard format that can be retrieved automatically and interpreted easily by user agents. P3P user agents will allow users to be informed of site practices (in both machine- and human-readable formats) and to automate dec...
Open graph description entity tag
Open graph title entity tag
Sites who has this tag are verfied by google to use WebMaster tools