Spam filtering is a bit like the various Pop Idol auditions.
Firstly, the candidate needs to actually find the audition site. You’d be
amazed at the number of turnups who say “Hi, I’m here for $foo” and are told
“Uhh, not here, sorry.” “Oh.”
Next you get those who’ve turned up at the right place but for the wrong
reason.
“Hi. \0x121\0x310\0x023……..” “Uhh, okay, Knitting World was last week.”
Next you get those who turn up at the right place but don’t listen.
“HI” “He..” “MAIL FROM” “but I’ve not said hel….” “RCPT TO”
Next you get those who turn up, but haven’t read the rules.
“Hi” “Hi there_how_are_you” “Ummm, no.”
Next you get those who turn up, understand the principles, but can’t remember
who they’re supposed to be talking to.
“Hi.” “Hi.” “RCPT TO: AAAAAAAAA@foo.com”, “Who?” RCPT TO: AAAAAAAAB@foo.com”, “Eh?”
And finally, you get those who turn up and sing like they’ve snorted
dysentry-infected liquiturds[0] a few minutes before.[1]
[0] My word, hands off.
[1] Yes, *.{cn, pl, hk, tw, ru, tr} I mean you.