[kopakabana]

> Google sells user data, but that isn't true; user data is only used for ad personalization.

And other companies getting referrals can’t connect the dots when they know the user clicking on the AdWords Ad and what the Ad was for?

Companies that work with big data companies run AdWords campaigns in Google for other companies, right?

Even if Google isn’t evil and does everything in the interest of privacy, if their ads, based on your preferences from your emails and browsing history, are used to direct you to some product, there is a way that other companies will learn of those preferences, store them, sell them, and use them.

[jayd16]

How is that a Google problem and not simply the other company tracking their own customers?

[visarga]

Google is targeting the ads, with each targeted ad they leak personal information about the users. Advertisers only have to pay and Google tells them who's matching whatever demographic they want. On the other hand print and billboard ads don't reveal personal information to the advertisers.