SoundCloud is the world's leading social sound platform where anyone can create sounds and share them everywhere. Recording and uploading sounds to SoundCloud lets people easily share them privately with their friends or publicly to blogs, sites and social networks. It takes just a click to share sounds to Twitter, Tumblr,...
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
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".