The change was announced in a blog post today, and will go into effect March 1. After that, if you are signed into your Google Account to use any service at all, the company can use that information on other services as well. As Google puts it:
This has been long coming. Google's privacy policies have been shifting towards sharing data across services, and away from data compartmentalization for some time. It's been consistently de-anonymizing you, initially requiring real names with Plus, for example, and then tying your Plus account to your Gmail account. But this is an entirely new level of sharing. And given all of the negative feedback that it had with Google+ privacy issues, it's especially troubling that it would take actions that further erode users' privacy.
What this means for you is that data from the things you search for, the emails you send, the places you look up on Google Maps, the videos you watch in YouTube, the discussions you have on Google+ will all be collected in one place. It seems like it will particularly affect Android users, whose real-time location (if they are Latitude users), Google Wallet data and much more will be up for grabs. And if you have signed up for Google+, odds are the company even knows your real name, as it still places hurdles in front of using a pseudonym (although it no longer explicitly requires users to go by their real names).
All of that data history will now be explicitly cross-referenced. Although it refers to providing users a better experience (read: more highly tailored results), presumably it is so that Google can deliver more highly targeted ads. (There has, incidentally, never been a better time to familiarize yourself with Google's Ad Preferences.)
So why are we calling this evil? Because Google changed the rules that it defined itself. Google built its reputation, and its multi-billion dollar business, on the promise of its "don't be evil" philosophy. That's been largely interpreted as meaning that Google will always put its users first, an interpretation that Google has cultivated and encouraged. Google has built a very lucrative company on the reputation of user respect. It has made billions of dollars in that effort to get us all under its feel-good tent. And now it's pulling the stakes out, collapsing it. It gives you a few weeks to pull your data out, using its data-liberation service, but if you want to use Google services, you have to agree to these rules.
Google's philosophy speaks directly to making money without doing evil. And it is very explicit in calling out advertising in the section on "evil." But while it emphasizes that ads should be relevant, obvious, and "not flashy," what seems to have been forgotten is a respect for its users privacy, and established practices.
Among its privacy principles, number four notes:
People have different privacy concerns and needs. To best serve the full range of our users, Google strives to offer them meaningful and fine-grained choices over the use of their personal information. We believe personal information should not be held hostage and we are committed to building products that let users export their personal information to other services. We don‘t sell users' personal information.
And much worse, it is an explicit reversal of its previous policies. As Google noted in 2009:
Previously, we only offered Personalized Search for signed-in users, and only when they had Web History enabled on their Google Accounts. What we're doing today is expanding Personalized Search so that we can provide it to signed-out users as well. This addition enables us to customize search results for you based upon 180 days of search activity linked to an anonymous cookie in your browser. It's completely separate from your Google Account and Web History (which are only available to signed-in users). You'll know when we customize results because a "View customizations" link will appear on the top right of the search results page. Clicking the link will let you see how we've customized your results and also let you turn off this type of customization.
The changes come shortly after Google revamped its search results to include social results it called Search plus Your World. Although that move has drawn heavy criticism from all over the Web, at least it gives users the option to not participate.