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.
Open graph description entity tag
A WebSite is a set of related web pages and other items typically served from a single web domain and accessible via URLs.
This page contains a meta robots tag which tells search engines and robots to index or not index the page.
Sites who has this tag are verfied by google to use WebMaster tools