This grand consolidation means that all of your Google account data will live in a single database that every Google service can access. Google Maps will have access to your Gmail data, which will have access to your YouTube history, and so on. Google insists that this change will ultimately benefit users, but privacy advocacy groups such as the Electronic Frontier Foundation fear that users will lose control over the personal data they've shared with Google.
If you'd like to exert control over your Google-based data, you still have time to act before March 1. Google's privacy settings can be tricky to navigate--the privacy Dashboard doesn't provide full access to all privacy settings, and Google's Data Liberation tool doesn't support everything yet. But these tips should help limit what Google can find out about you.
Check the Dashboard
Your first destination is Google Dashboard. It provides an overview of the information Google has stored on your account across many of its most popular services. To get started, go to google.com/dashboard and log in with your Google account (typically an email address). There, you can see much of the data that Google has on you--from your Google+ account to your Gmail account.
Take a few minutes to click through the various services and to review the information Google is storing. Then clear out any data you no longer want associated with your account.
Clear Your Google Web History
Google Web History keeps track of your Web browsing in order to help Google serve up more-relevant search results, According to the company, Google Web History "saves information about your web activity, including pages you visit and searches on Google. Over time, the service may use additional information about your activity on Google or other information you provide us in order to deliver a better search experience."
Even while you’re logged out of your Google account, Google achieve a similar effect by tracking your search history via a browser cookie.
To turn this off, visit google.com/history while signed into your Google account and click Remove all web history. In the next screen, click OK to confirm your decision, and thenceforth Google will no longer track your Web history for the sake of improving search accuracy. As the EFF notes, however, Google may still log this information for various internal purposes.
If you don't have a Google account, or if you're logged out of your account, visit google.com/history/optout and click Disable customizations based on search activity.
Tweak Your Ads Preferences
By default, Google serves up "personalized" ads, based on search queries or on the content of your Gmail messages. For example, if you run a search for "Mobile World Congress," Google may serve up an ad for a phone or a tablet. If you find that kind of activity too invasive (or just plain creepy), you can dig into Google's privacy settings to disable personalized ads.
Head on over to Google's Ad Preferences page; and in the left-hand column, under 'Ads on Search and Gmail', click Opt out. From there, click the Opt out button to the right, and Google will stop serving up personalized ads based on your search results.
You can also opt out of personalized ads that appear on other sites through Google's Web ad services. In the left-hand column of the same Ad Preferences page, under 'Ads on the Web', click Opt out, and then click the blue Opt out button to the right.
Liberate Your Data
If you want to remove some (but not all) of your personal data from multiple Google services, head over to Google Takeout, which lets you download a copy of your data from Google Buzz, Circles, Docs, Picasa Web Albums, Gmail contacts, and other tools and services. Get started by logging in to the Google Takeout page. Once there, you can download your data for all supported services, or you can pick and choose the data you want to download. Once you've chosen what you want to download, click the Create Archive button at the bottom of the page. Google Takeout will create an archive consisting of your downloadable data (it may take a few minutes for Google Takeout to create the archive for you).
After downloading the archive, you can delete the data from the individual Google services. Unfortunately, doing so is a manually operation--Google doesn't let you automatically delete the data you download from its servers. In addition, Google Takeout doesn't yet support all of Google’s services, so you won't be able to take everything with you. Still, some data removal is better than none.
The Nuclear Option: Delete Your Google Account
If you feel truly paranoid, you can remove your Google account completely. Deleting your account will mean losing all of the information associated with it, including your Gmail account, your Google+ profile, and anything you've stored within Google Docs.
If you're willing to take the leap, log in to your Google account and visit your account settings page. Scroll to the bottom and, under Services, click Close entire account and delete all services and info associated with it. On the next page, Google will ask you to confirm that you really, truly want to delete your account. Follow the instructions, enter your password, take a deep breath, and click Delete Google Account.
On the other hand, you may want to delete just your Google+ account. If so, scroll to the bottom of the account setting page, and click Delete profile and remove associated Google+ features. From there, you can delete your Google+ content or your entire Google profile, which will remove you from Google+, Google Buzz, and several other services.
We're all for personal privacy, of course, but we also appreciate convenience. If you feel the same way, and you can deal with the reality that Google probably already knows a lot about you (and will soon know even more), you can leave your Google account as it is.