Re: Summary of Issues Raised to date

   From: Laird Breyer <[email protected]>

   Yakov,

   There's one issue missing in your list, which came up in the header 
   compendium. POPFile also modifies the subject directly, which as I
   understand is necessary for filtering in Outlook Express. 
   There may be other filters who do this too.

Yes- but it is clear that ADV: in the subject line
is _always_ an indicator of spam.

That one (and only that one) appears to be safe.

But with a bit o thought, it seems very unlikely that any spammer
would add an "I am spam" flag; we really only have to avoid 
counterfeiting "legit" flags, and let the counterfeiters 
fake all of the "I am spam" flags they want.

     -Bill Yerazunis


   I would think that this practice is a prime candidate for
   standardization. Here are some issues with it:

   - Spoofed [category] tags. How does a filter deal with them?
   - Population explosion of [category] tags. In an email conversation,
     the tags become a nuisance just like Re: Re: Re: ...
   - If the tags are modified over an email conversation, or added late
     say, some of the threading algorithms are affected. For example, 
     Jamie Zawinski (http://www.jwz.org/doc/threading.html) describes a
     robust way of threading, which AFAIK is widely used. However, the
     algorithm sometimes compares subject strings directly to see if the 
     messages belong to a thread. Inserting/removing [category] tags in subjects
     could play havoc with the algorithm.
   - The tags can be skipped by the originating algorithm, but
     independent filters have no way of recognizing them (ie the [,]
     markers are much too common in mail subjects)

   It's rather distressing now that I've made a list of some of the problems.

   -- 
   Laird Breyer.