> The best example I remember is that it blocked websites that had the word "mistress" anywhere in it, thus denying access to all websites where the word "webmistress" could be found, regardless of its contents or information.

Where I work, we used to access the Internet through a proxy that had a very primitive content filter on it. It's since been dismantled, but when it was active, it was entertaining to figure out words that it would block. It did no actual "content" filtering, because it wouldn't look at page contents -- it would only look at the URL and search for keywords that appeared in it. I could not, for example view my own movie review of the movie "Babe" or its sequel, from work. I really wish we had written down all the wacky words that were filtered out, because some were bizarre, like "soapy." Soapy! And Dave thinks MY "bad word list" is too conservative.