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What's the most private search engine of them all?

Jul. 23, 2007 | In an effort to bolster its privacy cred, Microsoft has announced that it will allow Web searchers to opt-out of behaviorally targeted ads on its sites. Behavioral targeting keeps track of your habits as you move through Microsoft's network -- the system might serve you ads for a DVD store next week if it notices that you're searching for a DVD player today.

Microsoft also says it will now keep people's search data in its server logs for 18 months, after which it will "anonymize" that information. In the past, Microsoft, like many other search engines, kept the data indefinitely; look up a DVD player today and the company would have recorded your IP address and your search terms in its logs forever.

Microsoft's news follows similar recent privacy adjustments from Ask, Google and Yahoo, a result of pressure from the Federal Trade Commission, European regulators, and a desire to one-up each other in the war for privacy conscious users.

So what's the most private search engine? If you're looking to keep big companies out of your business, here's a handy run-down:

• Google: In March, the company announced that it would keep search logs for 18 months, after which it would make the data anonymous. Every time you use any search engine, the site keeps a note of your Internet address, your search query, and details from "cookies" you have on your computer. Search engines say they use that data to keep their engines running well. Google, for instance, uses search logs to run its spell checker, to track spam, fraud, and attacks on Google's and other Internet machines, as well as in an effort to comply with some regulations (for instance, anti-terrorism laws being contemplated by lawmakers in the U.S. and Europe).

  Google was the first major engine to set a time limit on this data. Now, when you search for something in Google, the site will keep your information for a year and a half -- after that, it'll scrub the search request to remove your Internet address and other potentially identifiable data. Google says that in order to comply with the law, 18 months is the shortest amount of time it has determined it must save the data.

  Google also does not "profile" users for marketing purposes. Google's ad business -- so far -- is based on keywords. You're served up an ad according to the search term you type in a for a specific search; Google makes no attempt to determine your demographical profile (your sex, your age, etc.) based on your searching history.

• Microsoft's Windows Live Search: Microsoft's 18-month server log plan works much the same was Google's. But Microsoft has another privacy problem: it makes extensive use of demographic profiling. Search Engine Land's Danny Sullivan points to this Wall Street Journal piece from December:
  If someone types in "compare car prices" on Live Search, Microsoft's computers note that the person is probably considering buying a vehicle. The computers then check with the list of Hotmail accounts to see if they have any information on the person. If they do, and an auto maker has paid Microsoft to target this type of person, the computer will automatically send a car ad when she next looks at a Microsoft Web page. As a result, people should see more ads that are of interest to them. "We know what Web sites they have visited and what key words they used," says Mr. Dobson. "We can deduce what their interests are." Microsoft says that in testing in the U.S., behavioral targeting increased clicks on ads by as much as 76 percent.

  It's this process that Microsoft is seeking to mitigate with its new profiling policy. The company says that users will soon be able to opt-out of demographic ad targeting if they choose.

• Ask.com: Last week the company announced that at some point in the future, it would also implement a new policy to keep users' search data for only 18 months. At some point in the future is the key news here. It's not clear when Ask will do this because it plans to activate the new policy at the same time that it unveils a new feature called Ask Eraser, which will theoretically allow users to request that the company erase search logs immediately.

  But how or whether Ask Eraser will work is a mystery, as Danny Sullivan notes. It is also unclear how Ask plans to get around the laws that Google says requires it to keep search data for at least 18 months.

• Yahoo: The company tells the New York Times that it will keep search-log data for only 13 months. That's five months fewer than Google and Microsoft keep your data, but still longer than Ask's theoretical immediate-deletion policy.

  Like Microsoft, Yahoo also behaviorally targets ads to people who visit its sites, but it has announced no plans to let people opt-out of this practice.

-- By Farhad Manjoo