LinkedIn Plugins are a way to drop LinkedIn functionality into websites.
Provides a widget which lets a visitor translate your webpage into a different language.
Google+ platform websites integration using the Google+ platform tag.
Convert anonymous visitors into leads and collect valuable lead intelligence with powerful forms that ask the right questions at the right times
Content Security Policy is best used as defense-in-depth, to reduce the harm caused by content injection attacks.
Open graph description entity tag
Sites who has this tag are verfied by google to use WebMaster tools
The http-equiv attribute provides an HTTP header for the information/value of the content attribute. The http-equiv attribute can be used to simulate an HTTP response header.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".