Everywhere you browse on the Web you leave traces in logs and databases and even the mildest case of paranoia will have you wondering just what could be known about you from these "footprints."

While for most users these traces are spread widely across hundreds or thousands of sites, some sites, notably the major search engines, get the greatest number of hits per individual and therefore amass huge quantities of tiny bits of user behavior data.

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Now you might believe that given the great mass that Google, for example, collects, you would be effectively anonymous but, alas, this is not so. By examining all the log entries for a given IP address or the same cookie-tracking ID, a surprising amount of personal detail can be discovered.

This was demonstrated earlier this month when AOL, in what can only be described as a temporary total loss of corporate sanity, made the three-month search histories of 658,000 users publicly available.

The New York Times did an analysis of the data and was able to identity user 4417749 as Thelma Arnold, a 62-year-old woman living in Georgia. The story is very revealing and shows the potential for your privacy to be reduced or even removed by even the most innocuous online activities.

As a counter to this problem a new free service has been launched: Lost in the Crowd published by Unspam Technologies.

Lost in the Crowd works by having users download a bookmarklet - a chunk of JavaScript that gets saved as a bookmark - and run it (by selecting the bookmark) when they next go to a search engine (there's a specific bookmarklet for each search engine).   

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