Google Publisher Tag (GPT) is an ad tagging library with which you can dynamically build ad requests. GPT takes key details from you such as ad unit name, ad size, and custom targeting, builds the request, and displays the ad on web pages or mobile apps.
Send live or pre-recorded audio and video to iPad, iPhone, iPod touch, and Mac using an ordinary web server.
Open graph description entity tag
Sites who has this tag are verfied by google to use WebMaster tools