The targeted advertising we see as we surf the web is either eminently practical…or downright creepy. Here’s a way to control a great deal of it:
“Yahoo Ad Interest Manager”
“Google Ads Preferences”
“Network Advertising Initiative”
As noted on the NAI page:
“Opting out of a network does not mean you will no longer receive online advertising. It does mean that the network from which you opted out will no longer deliver ads tailored to your Web preferences and usage patterns.”
Also, many of these settings have certain time-to-live settings, and are typically cookie-based, meaning that they can be computer-specific and affected by running adware cleaning programs.