Archive for January, 2006

The PING attribute

Friday, January 20th, 2006

Firefox have decided to implement the PING attribute, the idea of it is to ensure that what people click on can be tracked with minimum impact on the user. Currently tracking is done by a link to a url which then redirects to the correct site. This takes a fraction of a second, but it does take time, and if the middle site is down the user can’t get through to the end site, even if it’s up.

The PING attribute attempts to solve this by moving the tracking from the critical path into a seperate attribute which the browser POSTs to when the user “follows the hyperlink”. This feature also allows one new piece of functionality, the ability to track links within pages so <a href=”#’top” ping=””> would allow me to track how many times people used goto to top links.

The use case described in the documentation is “allowing advertisers to track click-through rates without obscuring the final target URI”. It also stresses that following the ping’s are optional, this has an important fact for anyone actually deploying adverts, if you use ping rather than the current reliable tracking methods then they will no longer be counted as a click-through. So if your ad agency changes to ping, you will lose clicks that you’re entitled to. I don’t know of any online Ad agencies which are planning to use ping, but the WHAT-WG specification is controlled by a Google employee.

Of course reputable Ad agencies have their click-throughs audited by independant auditors to ensure they are accurate, so any that switch to ping will soon be forced to switch back to ensure the results - and therefore the monies are accurately reported. It’s clear the use case described by the WHAT people is not met by the attribute, the only other use case mentioned is “track which off-site links are most popular”, hardly a particularly important use case, but if there are no downsides to the method, then does it matter?

Unfortunately there are downsides, existing tracking methods must end up at the site the user expects to go to, otherwise they’ll be annoyed, this method you can ping any site, for example
<a href=”” ping=”″> would ping a bugzilla page that causes a lot of processing on the remote server, and returns a lot of data. So this sort of simple Denial of Service method is made easy, users will never know it’s happening all they’ll just see a big slowdown in their connection as it spends its time requesting pointless resources. Then there’s the up-counting of clickthroughs itself, copy the ping attribute from your google advert onto your other links, then any link a user leaves the page from an advert click is clicked, this is hard to track as the ad provider is completely outside the link the only way to check is to see if the recieved links match the sent links.

Like much of the WHAT-WG proposals (but not all), this is a poorly thought out proposal and it’s disappointing that the browser vendors are not meeting it with the critical inspection they would any other proposal. PING fails to meet its own use cases and it introduces lots of potential for abuse, if you’re creating a user agent and thinking of implementing this - think hard about what it could be used for?