It’s hard to write about Firefox with an emphasis on security and privacy, or give practical configuration advice, because the developers keep adding configuration options, then discarding them, then reviving them. Mozilla has remained consistent in its excellent set of configuration options, which means that the step-by-step security and privacy setup for Mozilla detailed in my 2004 manual Computer Security for the Home and Small Office is still effective.

Firefox has not shown anything approaching this degree of consistency. For example, on my trusty Linux box, I have Firefox version 1.5.0.4, with a configuration option enabling me to block third party images. On my cursed Windows box, I have Firefox version 2.0.0.1, which lacks this option. It’s an important privacy issue, because there are invisible, 1-pixel-square images called web bugs often embedded in web pages by third parties – marketing outfits, usually – which are used to track our web sessions. Marketers prefer to call them “web beacons”, but they are, in fact, bugs.

They can be defeated quite easily, by preventing your browser from loading images from sites other than the one you are visiting. Perhaps 2.0.0.1 defaults to loading images only from the websites you visit, but by withdrawing the option, the developers have left me a good deal less confident.