In blogging, a ping is an XML-RPC-based push mechanism by which a weblog notifies a server that its content has been updated. An XML-RPC signal is sent from the weblog to one or more "Ping Server(s)" (controlled by the weblog) to notify a list of their "Services" of new content on the weblog.
A Ping Server may notify multiple services when pinged;
The technology was first introduced by Dave Winer to Weblogs.com in October 2001. Today, most blog authoring tools automatically ping one or more servers each time the blogger creates a new post or updates an old one.
Open ping servers, like Moreover Technologies' Weblogs.com, let other web services subscribe to a list of blogs that have recently pinged them. Blog search engines can provide fresh results very quickly by polling only the newly updated blogs. Similarly, aggregators use results from ping servers to tell subscribers which items on their subscription lists have fresh material.
In addition to open ping servers, there are also proprietary ping servers that gather information only for their own applications. Most of the major blog search engines operate such ping servers, and most Content Management Systems and Blogs provide an easy way to modify Ping Services
The use of ping servers to direct attention to recent blog posts has led to a rash of ping spam or sping, which attempts to direct readers to web pages that are not, in fact, recent blog posts. Examples:
Creators of ping spam or spam blogs may hope to benefit by creating pages to turn up in web searches for popular keywords. Typically, an individual spam post links to some external page that displays Google ads or offers a product for sale.
Although pinging adds no value to a website's rank-ability in search engines, it does help search engine Web crawlers discover content quicker, which may give it (the content) the visibility needed to attract traffic (often resulting in conversions such as sharing the website, which means additional backlinks, social shares, etc., which does help a website rank.