The greatest threat to your privacy may not come from cookies, spyware or websites tracking and analysing your web surfing habits.
Instead, it may come from search engines, which collect and store records of your searches. Search engines track your search terms, the sites you visit as a result of your searches, the times you conduct your searches and your IP address. This makes it possible to figure out who you are, what your likes and dislikes are, and what you do online.
Search records can be subpoenaed and used in any way the government sees fit. And the records can also be inadvertently released to the public, for all the world to see. For example, in August 2006, AOL accidentally published the search histories of 650,000 users, and that data soon spread throughout the internet.
Does this mean that you give up your privacy every time you visit a search engine? Not if you're smart about it. Follow these seven tips, and you'll go a long way toward keeping your search history private, no matter which search engine you use.
Tip No. 1: Don't log into search engines or their tools
If you log into a search engine, you make it easy for that search engine to build a comprehensive profile about you, because they know your identity as you search. You may think that you never log into search engines, but there's a good chance that you do, possibly without thinking about it. Long gone are the days when a search engine was only a search engine. Today, they're entire ecosystems of sites and services. Google, for example, offers dozens of services, including Gmail, online office software, blogging services and more. For most of them, you need to log in if you want to use them.
For privacy's sake, never do searches when you're logged into any of a search engine's services, such as its mail service. So, for example, when you're logged into Gmail, don't search the internet.
As a practical matter, this may be difficult to do, so another option is to use one browser such as Firefox for a service like Gmail, and another such as Internet Explorer for doing Google searches. That way, it will be much harder for the search engine to correlate your identity with your searches. For maximum safety, use an 'anonymising' service or software such as Tor for the browser that you use to search with.
If you don't like the idea of using two browsers, set up different profiles in your browser -- one for using mail, another for services from a search engine and another for doing actual searches. Again, this will make it harder for the search engine to correlate your searches with your identity.
Firefox lets you create separate profiles, but Internet Explorer doesn't. In Firefox, use the Profile Manager to create separate profiles. To do it, open a command prompt and navigate to the directory in which Firefox is installed. (Depending on your version, it may be in C:\Program Files\Mozilla Firefox.) Type firefox.exe -ProfileManager and press Enter. The Profile Manager, as shown in the nearby figure, appears. Click Create Profile and follow the wizard to create your profile. Create as many profiles as you like, then use different profiles for searching and using mail and other search engine services. For more details about creating and using profiles, see the Firefox help page How to Manage Profiles.
Tip No. 2: Keep yourself safe from Google
A simpler solution is to block only Google from placing cookies on your PC. How you do it varies from browser to browser. In Internet Explorer 7.0, for example, choose Tools, Internet Options, click the Privacy tab, then click the Sites button. In the 'Address of Web site' box, type in www.google.com, and click Block. From now on, when you visit Google, it won't be allowed to place a cookie on your hard disk, and it won't be able to track your searches.
In Firefox 2.0, select Tools, Options, select the Privacy tab, and click Exceptions. Then type www.google.com into the 'Address of Web site' box and click Block. (If you use another search engine, by the way, you can use this same technique to keep its cookies off your hard disk as well.)
Note that because Google won't be placing cookies on your hard disk, you may not be able to use various Google services, such as Gmail.
If you're a Firefox user, you can also use the CustomizeFirefox extension, which, among other things, 'anonymises' you when you use Google so that your searches can't be tracked.
Google has numerous services you can sign up for, including RSS readers called Google Reader and Google Groups, which let you read newsgroups and other discussion groups. The more Google services like this that you sign up for, the more information Google knows about you. In addition to your searches, it will know what blogs and newsgroups you read, for example. This makes it that much easier for the search giant to create a profile about you. So either don't sign up for those services or else create separate Google accounts for each of them, so that the search engine can't correlate all your interests.
Also, think carefully before turning on Google's Search History feature. Search History lets you revisit all your searches and shows what you've searched for every day. When you use Search History, Google stores a record of all your searches on its servers. If you're worried that that search history may fall into the wrong hands, or be subpoenaed by the government, simply don't use the service.
Tip No. 3: Regularly change your IP address
Search engines can correlate all your searches by tracking the IP address you're using and then using that to link together all the searches you perform on their sites. There's a simple way to get around this; regularly change your IP address.
Broadband providers assign you a dynamic IP address for using the Internet. That dynamic IP address typically stays assigned to your PC for a very long time. To get a new IP address, turn your cable modem or DSL modem off, leave it off for a few minutes and then turn it on again. Doing that clears your old IP address and gives you a new one.
If you're one of the few people who have a static IP address, for example, at work, you won't be able to use this technique. Instead, you'll have to turn to anonymous surfing with software such as Tor.
Tip No. 4: Use ixquick
Here's the easiest way to make sure that information about your searches can't be used to build a personal profile about you: Use a search engine that doesn't retain a history of your searches. That's what ixquick promises. It says it deletes all information about your searches within 48 hours, so the information simply isn't around for anyone to use. If the government subpoenas the data, there's nothing for them to get.
Tip No. 5: Don't include personal information in your searches
We've all 'Googled' ourselves at times, just to see what's out there on the web about us. But every time you use personal information in a search, such as your name, address and so on, you make it easy for a search engine to know who you are and then correlate searches with your name. Worse, it can lead to identity theft if you search for important personal details and someone gets hold of your search records. So try to avoid including information about yourself in your searches.
Tip No. 6: Do sensitive searches from a public hot spot
If you absolutely must do a search about personal information or do a search that is sensitive for some other reason, don't do it at home or at work. Instead, go to a public hot spot and do the search from there. Make sure to use a hot spot that doesn't require you to log in, or else your privacy can be compromised.
Tip No. 7: Avoid using your internet service provider's search engine
Your service provider knows your IP address, which means that it can track all the websites you visit. That's bad enough for your privacy, but if you also use its search engine, it will be able to correlate your IP address to your searches and build an even more comprehensive profile about you. That profile may be available to anyone with a subpoena. So don't use a service provider's search engine, such as http://search.comcast.net/.
Preston Gralla is a contributing editor for Computerworld, and the author of more than 35 books, including Windows Vista in a Nutshell.