Recently, as I was browsing the Firefox add-ons directory, I stumbled across a few interesting looking plug-ins that I thought I would try out. I downloaded and installed them. Being the curious developer type that I am, I decided to dissect the plug-ins to see what they did internally. One of the plug-ins in particular seemed quite innocent. It gave the browser the ability to highlight specific keywords on a page so that it would be easier to find them. Seemingly harmless, right? Well, after further investigation, I discovered something interesting. This plug-in, after clicking the highlight button, would replace all the Google AdSense ads on the page with different ads. I discovered this by using the Live HTTP Headers plug-in, another add-on for Firefox. It allows you to view the ingoing and outgoing http requests being sent. Every time I clicked the highlight button it would make a request to the Google AdSense server. Then, using the Firebug plug-in, I was able to profile the page and see what JavaScript was running. The plugin traversed the DOM, replacing the highlighted text and also finding the Google Adsense ads and replacing them with different ads. What does this mean? Well, either there was a mistake, which I doubt, or the person who wrote the plug-in is raking in a fair amount of dough. I’m pretty sure that this is against the Google AdSense Terms of Service, but was quite an ingenious idea while it lasted.

This entry was posted on Monday, July 9th, 2007 at 10:41 pm and is filed under Development, Ideas, Random. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.