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 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.
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.
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.
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.