Gmail/google uses the spamav/clamav, spamd and spamassasin rating to determine what is spam and what is not.
Part of that is based on their custom signatures, which send to spam folders based on "intelligent" format. This "spamav/clamav" signature is updated on their servers hourly (or depending on the conf file).
These rules are run before your filters, and can catch things with "..'.." etc. URI encoding exploits and virus can attach to even the Subject line, and are scraped for good reason.
Use the Source Luke - ask Google?
http://wapedia.mobi/en/Obnosis ||
http://en.wiktionary.org/wiki/obnosis | Obnosis.com (503)754-4452
Laugh at this MSN Footer
> Date: Fri, 10 Oct 2008 10:43:45 -0700
> From: joe@actionline.com
> To: plug-discuss@lists.plug.phoenix.az.us
> Subject: OT: Gmail filter errors
>
> I've searched the 'net and tried Gmail forums, but can't find
> any help anywhere else, so I'll try the best source, even though
> this is OT.
>
> 1. Every day, I have some legitimate email that Gmail sends
> to spam, so I still have to go through it every day to retrieve
> those legitimate items.
>
> 2. Having created several hundred Gmail filters to battle this
> never-ending spam problem (and to try to cut down on the number
> of emails overrunning the spam folder that I have to scan through
> every day, I now find that some legitimate email is now getting filtered
> and sent to trash, also.
>
> So, I have been running all kinds of tests to try to figure out why
> this is happening. One example is a PLUG email that just went
> into trash with the subject: "OT: I've Been Burgled!"
>
> After examining my filters and not finding any that should have
> caused this problem, I tried sending a dozen different email
> messages to myself with various combinations of criteria to
> identify what might be causing the problem. I only have filters
> set up for From: / To: / and Subject: , so I tried every possible
> combination of character strings and finally narrowed the
> problem down to one word in the subject line that causes
> the errant filtering to trash of this item ... the word: "I've"
>
> I do not have the word "I've" in any of my filters. So can anyone
> suggest any possible reason or remedy for this anomaly?
>
> Another very strange thing about this is that when I pull up a
> list of all my filters and try to do a search for the word "I've"
> or even "Ive" I get zero hits. However, in the process of testing
> this, I discovered that when I search for some other words, in
> my list of filters, I have found that search returns several
> more hits for some words or names than actually appear in
> the list. That is really strange.
>
> For example, if I search for the name "Greg" search returns
> five (5) hits, but there are only two occurences of that name
> in my list of filters. This happens on many other words, also.
>
> Hope someone can provide some help with these problems.
>
> Google doesn't respond and I can't find any help in any
> Gmail forum.
>
> Joe
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