The Strange Emails, page 1

I too have wondered about the true nature of these emails - many do not contain any links to products nor any type of obvious scam. The best I can come up with as an explanation is spamfilter 'deprogramming'. Most mail servers use spamfilters to block the spam in an early stage (before it even gets delivered). To keep up with the current spamming trend, most of those spamfilters employ some kind of learning technique, for example the Bayesian technique:

Bayesian filtering takes folders of known spam and known ham and identifies words or phrases ("tokens") that only show up in spam and tokens that only show up in ham. When a new message is being scored in the future, if it contains a lot of spammy tokens, it spam score goes up. If it contains a lot of hammy tokens, its spam score goes down. This is a much better approach than static phrase identification as it handles the case where "Nigeria" might be a legitimate word in an email to a travel agent's office, or "breast" would be legitimate in an email to a women's clinic.

(from www.stearns.org...)
The algorithm that decides how to learn from the input of mails (both spam and normal) may have some flaws or weaknesses that makes it exploitable. In the above filtering technique, an obvious problem arises when it first rates an email as either spam or ham, then learns the words in that very email as either 'spammy' or 'hammy' - it's circular.

Imagine the following - a spamfilter on a mailserver recognizes mail as either spam or valid mail. It's an elaborate guess made by matching for certain words (e.g. mortgage, diploma) but more importantly, being able to adapt to new words through rating the incoming content. Now let's say an attacker sends a lot of emails with normal words but the email headers don't match up (as they often do when the email is forged in a dirty way) - the spam filter will catch them and assign those normal words as 'spammy' tokens. If this attack works, then the spamfilter may start to block all valid emails as well! In effect, an administrator may have to lower the spamfilter's gate a little just in order to get the normal emails sent through .. and thereby the spam as well.

Most spamfilters employ too much techniques to be fooled so easily, luckily. It does however mean that some of these spammed emails may come through.

By the way, every now and then I do read those emails to see if they could have some other meaning.. Like the "Help, I'm being held prisoner in the factory" kind of messages

you never know, right!