I'll spare you the details of whose site I noticed this on, as it's just another right-wing god-bothering nutjob in the US trolling for hits and have little interest in giving publicity.
The alleged cause of his perturbation (though it's more attention-grabbing) is Adblock Plus, a filter that removes elements from pages before the browser renders them.
A quick google, and it seems there's more ad blocking software available for IE than any other browser. I should mention I haven't tried any of these, but the picks below for various browsers don't trigger any of my warning senses.
Free ad blockers based on Internet Explorer
http://www.quero.at/ (also sorts IE7 toolbar issues)
Free ad blockers for Opera and Safari
http://operawiki.info/OperaAdblock (explaining the built-in content blocker)
For the techies, a proxy for all browsers
I would suggest not blocking ads on sites you like, and whitelisting friendly and trustable ad providers such as Google, Amazon and Project Wonderful. I would also suggest avoiding IE, on the basis that the last decade has seen a large number of critical security issues occur in its development. (Where "critical" means that a site can run any code it likes on your machine if you simply visit a site. Most other vulnerabilities are chicken-feed by comparison.)
In each iteration of web marketing, people adopting ad blockers has been driven by the advertisers going too far — page elements that are animated / flash / make sounds, poor content-to-ad ratios, intrusive pop-ups — and their implication in the spread of viruses through OS flaws. The trouble is that once users move to blocking they're unlikely to switch the filtering off, and "innocent" advertising is highly likely to be caught alongside the truly annoying stuff. People who've abused web advertising are ruining the model for those who offered relevant, non-intrusive ads.