At any given time most of our computers have any number of "cookies" attached to them allowing web companies to record all the places we visit online.  Advertisers use this data to serve up contextual ads, ones that you will find relevant based on your web visiting habits.  Sounds good in theory but many think it reeks of Big Brother type overtones.  Google has a little known solution for this problem and kudos for them making it available.  Check it out and decide for yourself who you want tagging along on your web adventures.