Why Google Built Incognito Mode

Everyone loves Incognito Mode (or what is commonly called "Porn Mode"). In Chrome you can quickly open up a new incognito window and any browsing history is stored in a silo and cleared out when the window is closed. Not only is it useful for visiting sites you don't want others to know that you visited, it's very useful in testing sites, checking your email at a friends house, etc.

I always wondered what the motivation was behind adding this to Chrome - obviously it's a nice feature for users but when Google does things there is almost always another reason. Google Plus+ is a great new product, but the real motivation is to get all that data for better targeting of ads.

But it hit me the other day - it makes complete sense for Google to create Incognito Mode. I Googled real quick to see if anyone else had come to the same conclusion, the only relevant post I found was on Quora.

The Google rep dodges the question - and what would have been a pretty obvious answer if you take a minute to think about Google's core business.

The reason that Incognito is such a great feature for Google to build is that over time it will reduce the cookie deletion rate of web browsers.

Cookies are used in a number of key ways in advertising. Cookies are used to track unique visitors, to enable frequency capping (how many times a person should see a certain ad), but most importantly they are used for behavioral targeting and retargeting. The more often someone clears out their cookies it resets all of these values - which directly translates into less targeted ads being sold. This directly translates into money lost for Google.

Higher Cookie Deletion Rate = Less Revenue for Google

The inverse is true as well. If Google can reduce the cookie deletion rate then it will increase revenue for Google. I am sure someone at Google has calculated what every 1/10 of a percentage point change in cookie deletion rate means for revenue.

Once Google built it they knew the other browsers would have to follow suit - FireFox and IE already include their own versions of Incognito Mode. Pretty brilliant when you think about it (and good for the entire ad industry), but not as innocent as a feature as it might first appear.

• James

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