Physical Traces of Shoppers Market researchers have recently begun observing the Web sites that people visit. Facebook, for instance, has used an ad system called "Beacon" that reports back to Facebook on a member's activities when the member visits any other site that also uses the Beacon system (Perez, 2007). So, even after a member has signed off from Facebook and left the site, Beacon keeps track of the other sites that the member visits for Facebook.

Required: List some advantages and disadvantages that this type of research might have over surveys of consumer attitudes.