Re: Problems with Bayesian filtering

Craig Hughes wrote:
> Note that the spammers are now wise to those of us who look for x-on-x 
> (eg white-on-white) text.  They have started to play with luminosity, so 
> that the text is eg 0xFFFFFE on white...  You'll want to calculate a 
> luminosity difference between the ink color and background color rather 
> than just compare them for equality.

Yes, and this is also covered in POPFile.  I've been gathering up all 
the tricks I can find here: http://www.sophos.com/spaminfo/fieldguide/

The latest twist is that I'm starting to see very widespread use of CSS 
to recycle invisible ink and camouflage tricks to fool filters that 
don't understand CSS.

John.