Spin.js dynamically creates spinning activity indicators that can be used as resolution-independent replacement for AJAX loading GIFs.
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
Indicates that the site provides an interface specifically for searching the document and its related resources.
By adding rel="home" to a hyperlink, a page indicates that the destination of that hyperlink is the homepage of the site in which the current page appears.