A friend of mine sent me this link,
whyfirsfoxisblocked.com, which apparently some sites send you to if they detect the Firefox useragent. Now the first thing that is stupid about this site is the fact you can easily change the useragent in Firefox using the Useragent Switcher extension. But the main stupidity of that site is this.
AdBlockPlus denies site owners the freedom to block AdBlockPlus users, therefore all FireFox users (except those using IETab) are blocked. It's a simple matter of opposing the censorship on the part of AdBlockPlus and therefore the support offered to them by Mozilla.
Hmm hate to burst their bubble but you can install
IE7Pro for IE 7 (funny that). Which provides a host of features including
AD Blocker which works in exactly the same way as AdBlock Plus on Firefox. You will also note that their is no way of contacting the owners of WhyFirefoxIsBlocked.com.
A more complete list of features for IE7Pro is Tab Enhance, Super Drag Drop,Inline Search,Spell Check, Crash Recovery, Proxy Switcher, Mouse Gesture, user script, User Agent Switcher, AD Blocker and Flash Block.