I have NEVER had a problem with Mail's spam filters in the four years I've been using it... it always piled up nicely in my junk box. Now all the sudden I am getting spam in my mailbox[es] and its really starting to annoy me. Whats going on?
I don't think its the server, as I have always gotten a healthy allotment of spam. What's strange is Mail isn't filtering it as efficiently as before. This holds true for my gmail, sbcglobal and website accounts, all of which I check via Mail.
I've recently started to receive spam on my .mac account and all of it is sent as .gif attachments, so I just set up a filter to dump all mail with a .gif attachment from someone not in my address book straight in to my junk folder.
Spam is not natural.
Spam is not static.
Spam is a cost to you--either in time, money, and/or effort required to block or delete it.
Spam is the way that a lot of unsavory characters make a living.
Spam authors and the vendors of the tools of their trade have a financial incentive to develop workarounds for whichever spam-blocking technology you use.
Spam filters must be updated and/or retrained periodically to remain effective.