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...
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
This page contains a meta robots tag which tells search engines and robots to index or not index the page.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".