Re: Why Spam is a problem

[John Stracke <jstracke at centivinc.com>]

stanislav shalunov wrote:

> Further, in its *present* form, where unfamiliar words are given 0.2
> spam probability, easily defeated by just adding a lot of randomly
> generated `words' like 9nscS9Ft, iuiF0kKw, 6AycPEbU, nsUdjGeP, etc.
> Given enough of these, the Bayesian probability formula will declare
> even a piece of mail that consists of a sales pitch for a pornographic
> web site have a probability of being spam that is arbitrarily close to
> 0.2.
>  
Is that true? The approach described looks only at the 15 words furthest 
from 0.5; it seems likely that most messages that would rank at 0.9 or 
above would have enough spam-words that words at 0.2 wouldn't show up.

One thing that would be necessary, and that the author doesn't mention, 
would be to decode content-encodings before applying the filter; 
otherwise spammers could just base64 all their messages.

--
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|John Stracke      |jstracke at centivinc.com                    |
|Principal Engineer|http://www.centivinc.com                  |
|Centiv            |My opinions are my own.                   |
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