Google+ platform websites integration using the Google+ platform tag.
Pinterest is a social networking site with a visually-pleasing virtual pinboard interface. Users collect photos and link to products they love, creating their own pinboards and following the pinboards of other people whom they find interesting. The site has experienced rapid growth in recent months.
Meta Keywords are a specific type of meta tag that appear in the HTML code of a Web page and help tell search engines what the topic of the page is.
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.