Earlier, we learned how to block ads at the OS level. Blocking ads through the browser is awesome, but advertising these days is all about making inroads to the desktop. Even though Microsoft claims that their business is software, Live Messenger seems to be an ad vehicle. I quickly became tired of video ads constantly showing up in Live Messenger (especially those insipid Tru dating site ads) that would play as soon as the cursor went over them, so I resolved to do something about it. I fired up Fiddler, a proxy that allows you to view HTTP traffic. I saw several random requests for rad.msn.com, and upon further examination saw that it was serving ad content, which depending on the content type, would be handled appropriately by Live Messenger’s ad box.

I added rad.msn.com to my hosts file, and the ads were now blocked. Since there was now a blank box, I decided to go a step further and replace the image. I tried this before with a program that patched the ad out of the executable, but this isn’t a long-term solution, since any software update will require waiting on a new version of the patcher, and a subsequent re-patching. If I just serve a different image up, it’s fairly future-proof because Messenger is one the wiser. No matter what subdirectory or file is being requested by Messenger, this script will always throw back the custom image.

Using the index.php file we ended up with on our last ad-blocking adventure, we will add the following before the html is sent to the browser:

// if it's live messenger, spit out an image and exit
if ($host == 'rad.msn.com') {
$filename = 'false-ad.jpg';
if (file_exists($filename)) {
$handle = fopen($filename, "r");
$contents = fread($handle, filesize($filename));
header("Content-type: image/jpeg");
echo $contents;
}
exit();
}

The exit() is added so we can bail out early after serving my custom image, and not serve up the normal adblock page (that I see in my browsers). The image size for the Live Messenger ad is 231×60 pixels.

I opted for an image that would blend in with the skin I use for Live Messenger, but wasn’t just a “blank space here” image. The skin shown is Oil Slick for Messenger Plus! Live.