Last week Microsoft announced it intends to launch Windows 8 with Do Not Track (DNT) as the default setting set for the included version of their web browser Internet Explorer (IE10). It has caused much controversy and gnashing of teeth among digital advertising proponents.

What is DNT and how does it work? 

To answer that, first a little bit about the way browesers and web servers work:  any time you tell your browser to navigate to a web address, your browser makes a call to the server and asks the server to send back data. So when I type www.espn.com into my browser it contacts the servers at ESPN and asks them to send back the information I know to be ESPN.com.  What the servers at ESPN can also send back is some tracking software to see where else I go and what I do on the web, and to store any preferences I may set for that site. (I don't know if ESPN does or does not track its visitors, but I do know this is very common to web publishers.)

DNT is a setting on the browser that tells the web server not use that tracking technology with this user. 

What does this mean? 

That's part of the problem—no one really agrees what it means when a DNT signal is received by a web server from a browser.  Does it mean collect information on what I do on your site but not the rest of the web? Or does it mean don't watch what I do at all? What kinds of tracking mechanisms are affected by this signal?  It's not yet clear.

As Microsoft's Chief Privacy Officer, Brendon Lynch, states in his blog post from May 31, "At the moment there is not yet an agreed definition of how to respond to a DNT signal."  Adding to the confusion is the fact there is also no mechanism forcing web servers to obey the DNT signal.  Which means they can simply choose to track you anyway.    

Why would Microsoft do this? 

In 2007, several consumer advocacy groups asked the Federal Trade Commission to create a Do Not Track list for online advertising. Microsoft says it's responding to these requests and "putting people first" by placing privacy controls in the hands of the people.

Suppose for a second that the DNT signal means no publisher is allowed to collect any information on you or your web travels. Then consider that IE market share hovers between 30% and 55%. Add to this the low probability most users will look for or change the DNT settings on their browser.  This would mean personalized experiences on the web would go away for those of us with the DNT signal set to "on."

Online advertising would go back to the days of scattershot ads. Because advertisers wouldn't be able to gather insights from your behavior on the web, they can no longer tailor their offers or experiences to you. 

I suspect this is a move designed to generate goodwill for Microsoft with consumers now, all the while striking a galancing blow to Google. In the end, I'd guess IE10 will ship with the DNT signal off, with very explicit intstructions on how to turn it on. 

We'll all have to stay tuned to see how this all shakes out. Just today, Ad Age reports that W3C, the international organization that sets standards for web protocols, "is preparing to label Microsoft's browser as 'noncompliant,' setting up a showdown between Redmond, web-standards creators and the rest of the online-ad ecosystem."

How do you think this controversy will affect the online advertising world?