Well we know that we are being tracked all the while by stealth hidden ways via webbugs even after we have left the website in question (for instance take Fido server fetchback tracking). Interesting discussions to block them are to be found here: https://nodpi.org/forum/index.php/topic,673.0.html
There are other ways to handle these nuisances, block them with a specific setting option in NoScript-Options-Advanced, Forbid “Web Bugs”. Another way to do this selectively for trackers is with the Ghostery extension for the Mozilla browser. Enjoy,
I explain a little bit more. Inside IE there is a tool bugnosis to show webbugs. To get everyone up-to-date, web bugs are small gifs (usually) that are hidden in certain websites (in banners and other graphics) or HTML emails. Like cookies, web bugs are placed in your browser and track you, but web bugs also share your information with other web bugs you may run across while surfing the web. They can use this information to possibly send you spam, or worse depending on the bug you’ve run across. You can take measures to protect yourself from these web bugs by getting some ad blocking software and creating tougher settings in your Internet browser (such as prompt for internet cookies). Also, when you get done with your Internet session you should clean out your temp Internet files, and cookies.
An example for you. A controversial US online advertising company has turned to agency support to launch its services in the UK. NebuAd analyses the websites people visit, so that it can deliver online advertising based on their interests. Re the FAQ: http://w2.eff.org/Privacy/Marketing/web_bug.html
It means that the ads people encounter on the web can change according to previous websites they have visited…thats just it they be sending out adverts on post data after the fact after you already done what you wanted to do, so they be coming in last not very good is it, the real losers will be the companys who paid them for the ad to be served and us as our data will be sold on. So they only get the wiser and companies and users both loose out. You certainly do not need to block such a tracker, won’t you? How to block in IE? http://www.wilderssecurity.com/showthread.php?t=176546
The tool to do so in IE seems to have been discontinued, it was bugnosis,
Also a good tool found up here myProxy: htxp://www.thenautilus.net/cgit/myProxy/tree/adzap/scripts/squid_redirect
Do not use this tool any longer because Bitdefender TrafficLight flags it as a phishing site (updated Febr.16 2012)