Every year SPAM filtering becomes more aggressive. That's bad news for companies who use email to market, but it's also bad news for everyone else. For example, I've had some really important emails (like from my tax accountant) get SPAM-flagged.
Of course, I'm against the sending of SPAM. Indeed, in my free weekly newsletter (where I frequently discuss these issues) , I emphasize that it's always best to send personal emails that show forethought rather than email blasts.
Today, however, a SPAM filter can end up catching even a completely personalize email that the sender has specifically written to an individual who could benefit from reading what the sender has to say.