Web Bugs’ are tiny graphics on a Web page or in an email designed to monitor who is reading the page or message. They can tell the snoops a whole host of things about your net use, and we’ve been hearing about them an awful lot in the last few privacy-challenging weeks. But would you know how to tell if you’ve been bugged?Visiting Richard M. Smith’s Web Bug FAQ would be a good way to make sure you understand how the little devils do their pernicious work. Referred to euphemistically by the internet advertising community as  ‘clear GIFs’, ‘1-by-1 GIFs’ and ‘invisible GIFs’, the bugs are often made invisible to hide the fact that you’re being monitored. But they don’t have to invisible to get information from you, which can include the IP address of your computer, your email address, the time you unknowingly viewed the Web Bug, and the kind of client you used to do it. What are they used for? Well, ad networks use these kinds of bugs to add information to a personal profile of what sites a person is visiting. This personal profile, which is stored in a database belonging to the ad network, then determines what kind of banner you’re shown when you visit a site.  Web Bugs can also be used to find out if a particular email message has been read by someone and if so, when the message was read. It can provide the IP address of the recipient, even if the recipient is attempting to remain anonymous. Because of this, bugs are often used in spam mailouts to measure how many people have viewed the same mail message in a marketing campaign.Web bugging is a fairly widespread practice by any account, with big names like Barnes and Noble, eToys, Cooking.com, Microsoft and InfoBeat all using Web Bugs to collect information on their users.  Many say Web site privacy policies are failing to disclose the use of Web Bugs and that the general practice of online profiling by third-party ad networks should at least be mentioned in privacy policies. The idea that an outsider could be tracking when you read your email is certainly disturbing - as, indeed, is any kind of secret monitoring of your behaviour. But what’s your best defense against Web Bugs? In short, turn off cookies. That’s right: turn the cookies off. What did they ever do for you anyway? Remember a few passwords? Purleese. Ignore IE5’s complaints - disable ‘em. And delete the ones that are already in the folder. And if that’s got you feeling queasy with technofear, a helping hand can be found at the Junkbusters Web site.  All you need to know about bugging, and being bugged: Richard M. Smith’s eminently useful  Web Bug FAQ