Google being Google, it has been very upfront about the changes and has of course written a number of informative blog posts on the topic.
Really, not much has really changed. Google has always used very powerful and intelligent algorithms to tailor content to you. Think of the auto-complete, targeted ads that might appear in on your Google search page, and even suggestions to follow people or brands in Google+.
What the policy does do is allows Google to build a complete history and profile of your online habits. With this information, Google can then target specific content towards you. Google says that by doing this, you will have a better experience and will no longer be seeing irrelevant advertisements or links that really don’t suit your needs and wants.
If you don’t like this new policy, you can choose to stop using Google products that require to have a Google account (this will limit some of the profile building) – such as Gmail.
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Tagged → important Google updates