How to Protect Your Privacy on Google
1. Know your privacy rights: Use the Google Privacy Center. This site includes all of Google's privacy policies, as well as privacy best practices for each of its products and services. Although the "legalese" of privacy policies can be difficult to understand, Google's Privacy Channel offers a library of short YouTube videos with practical tips on protecting your data when using Google products and services. Try the "Google Search Privacy" and "Google Privacy Tips" series.
2. Protect your content on the services you use. Some content that Google stores for you, such as photos uploaded in Picasa Web Albums, are public by default. You can protect your privacy when you upload photos by choosing the appropriate checkbox.
Choices include "unlisted" (accessible only if you have the Web link, and not indexed by Web search engines) or private (viewable only by named users who must sign in).
Another example: You can take a Google Chat "off the record" if you don't want the instant messaging transcript stored.
In contrast, Google Latitude, which tracks your whereabouts by way of GPS-enabled cell phones, does not share your location data by default. You must authorize others to see it. Latitude stores your last known location, but not your history.
3. Turn off the suggestion feature in the Chrome browser. By default, Chrome retains a history of Web sites you've visited -- and the full text of those pages -- so it can try to guess which Web address you want as you type in the "Omnibox."
You can turn the feature off by going to "Under the Hood" under Options and unchecking the "Use a suggestion service" box. You can also select other privacy options, including surfing in Chrome's "incognito" mode.
4. Turn off Web History. You may have turned on the Web History option, also called Personalized Search, when you first created your Google account. If so, Google may be maintaining a "personalized" search history for your use.
Google does not use this data to target ads. It uses a separate search history, stored in Google's server logs and associated with a browser cookie, for that purpose. That data is "anonymized" after nine months. But your Web History is retained forever, unless you turn it off or delete the contents.
5. Opt out of interest-based ad serving. As of March 11, Google and third parties in its AdSense network are using not just contextual information (what you're searching for) but a history of previously viewed Web pages to serve up targeted advertising. The idea is to serve up ads that are more relevant to your interests.
You can remove interest categories Google has attributed to you or add others by visiting its Ad Preferences page. You can also opt out. To make the opt-out setting permanent, however, you'll need to install a plug-in for each browser you use. It's available for IE, Firefox, Chrome and Safari.
6. Add SSL to Gmail. You can encrypt e-mails you read and create in Gmail. Your log-in data is encrypted by default by SSL encryption, but SSL is turned off when you interact with your e-mail, because it can slow performance.
You'll find the option in Settings under the General tab. Scroll to the bottom of the screen and select the "Always use https" option under the Browser Connection setting.