There's a new feature in Firefox trunk (the development branch that will become Firefox 2.0) that is going to raise a storm of complaint: It is the addition of the ping attribute in the anchors and area tags.When the anchor is clicked, Firefox browsers that haven't had link pings disabled will send an HTTP POST request to the specified URL. The point of this feature is to make link tracking easier.Typically, Web sites would have to resort to all kinds of devious redirection tricks to be able to get more than a log trace of URLs requested but the ping attribute makes identifying which specific link has been clicked completely painless.The specification is the result of the Web Hypertext Application Technology Working Group (WHATWG), "a loose unofficial collaboration of Web browser manufacturers and interested parties who wish to develop new technologies designed to allow authors to write and deploy applications over the World Wide Web."The ping attribute is a result of the group's working draft Web Applications 1.0.In use, the ping attribute looks like this:Here.In fact, the ping attribute can include more than one URL in a space delimited list, thus:Here.People with privacy concerns may be worried by this but in practice it is no more invasive than cookies or the use of Ajax to do the same thing. In Firefox 2.0 the developers plan to display the URLs to be pinged in the status bar and the feature can be turned off by the user; the consequence for Web sites that require the ability to track may turn out to be the same as for user who disable cookies - these sites won't allow users to browse.It is worth noting, as was pointed out in the blog "Fried Fish": "Web sites already do something similar [link pings] in IE by exploiting a bug with the way images load. There's of course no pref to disable that bug ;-)"