Pingback
Pingback is a method of notifying web authors when their documents or pages are linked . This allows authors to keep track of who refers to their pages or cites parts of them. Pingbacks are sent via an XML-RPC interface.
functionality
A pingback is sent when a reference is made from one document (source document) to another document (target document).
In order to receive pingbacks, a website operator must send either an HTTP header ( X-Pingback) or an HTML element ( <link rel="pingback">) with each document , in which the URL of an XML-RPC interface is specified.
This XML-RPC interface has a single method: pingback.pingwhich takes two arguments. First, the URL of the source document, second, the URL of the target document.
In order to send pingbacks, when a new document is published, all linked documents must be checked to see whether a pingback interface is specified. In this case the pingback method is called with the appropriate URLs as arguments.