Smaller Clickable Area To Affect AdSense Ad Trackers
There’s a lot of activity over at ProBlogger about the news that Google is making AdSense ad units less clickable. Personally, I don’t think it’s such a big deal: most publishers make the titles blue (the universal link color) and most users click on the ad titles anyhow. This is more about preventing accidental clicks. In the long run it will benefit everyone because advertisers will have more trust in the system.
One side effect,though, is that AdSense ad tracking scripts will be much less accurate. Let me explain.
How Ad Tracking Works
Ad tracking scripts have two parts to them: a JavaScript script that you insert on the pages you want tracked and a PHP or Perl script that runs on the server. When someone clicks an ad, the JavaScript script detects this and communicates the information to the server script, which then logs it to a database. The site owner can then query the database at any point in time to view data about the ad clicks for that site.
There’s a limit to what the JavaScript script can track, however, due to the nature of how the ads are served. AdSense ads are served using an <iframe> tag, which lets you seamlessly embed one page into another. Internally, though, they’re still separate pages: one page (the one with the iframe) is hosted on your domain and the other (the ad unit) is hosted on google.com. Here’s what I mean:
As a security measure, most browsers prevent cross-site scripting, which means that a script loaded from one site (in this case, yours) cannot access or affect the parts of a page that are loaded from another site (in this case, Google). The <iframe> is part of your page, so a script can attach itself to it and listen for mouse and click events on the iframe, but it can’t do the same for the contents of the iframe.
What Does This Mean?
Since the tracking script can only track what happens to the <iframe> and not individual HTML elements within the iframe, Google’s change to the clickable area means that tracking scripts are suddenly less effective. Before there was a (pretty much) one-to-one mapping from AdSense click to iframe click. Now, though, some of the clicks on the iframe won’t actually correspond to valid ad unit clicks. So the tracking script will overreport clicks.
This is the second blow to tracking scripts that Google’s done recently. A few months ago they changed the way the ads were being served to make it impossible for scripts to tell which URL was being clicked on. Now the scripts won’t be as accurate.
Tracking scripts are still useful, mind you, if only because Google limits publishers to 200 channels per account. If you have a lot of content and/or a lot of sites, you’ll still find a tracking script useful… just not as useful as before.
Eric Giguere is the author of several printed books and knows a thing or two about content monetization. Subscribe to his AdSense blog today and never miss any of his insightful comments. And the not-so-insightful ones, for that matter.
Comments
One Response to “Smaller Clickable Area To Affect AdSense Ad Trackers”
I certainly welcome this, I’ve always thought it stupid that the whole ad area was clickable.
The only accidental clicks I’ve made on my own sites have been clicking on white space to bring a window to the front of the display and then having the cold rush as you realise you’ve clicked on your own ads.
Well, I run a greasemonkey script now to stop me clicking on my own ads. But it used to be a problem.
It’ll also reduce accidental clicks from genuine visitors on site where people place navigation and “next page” links dangerously close to ad units in the hope of catching a few stray clicks.