[This was for Dave Farber's list, to explain why an editorial on spam ended up regarded as spam. Didn't make the cut - or maybe it got rejected somewhere along the way as spam ...]
[For IP] Ah, another easy one. Just from my experience, the problem is with the sentence:
"One technique is to misspell words, like "Viagra" or "pornography," that set off the filters.
You can't say "Viagra" or "pornography". Because if you say "Viagra" or "pornography", even in the context of discussing why you can't say "Viagra" or "pornography", well, we see what happens :-)
I'm reminded of this scene from the movie Life Of Brian:
http://www.stone-dead.asn.au/movies/life-of-brian/scene-05.html
MATTHIAS:
Look. I don't think it ought to be blasphemy, just saying 'Jehovah'.
CROWD:
Oooh! He said it again! Oooh!...
OFFICIAL:
You're only making it worse for yourself!
MATTHIAS:
Making it worse?! How could it be worse?! Jehovah! Jehovah! Jehovah!
CROWD:
Oooooh!...
OFFICIAL:
I'm warning you. If you say 'Jehovah' once more--
[MRS. A. stones OFFICIAL]
Right. Who threw that?