I know that everyone likes to say that email is broken, and to some degree I agreed with this due to the fact that the amount of spam I used to get far outweighted the legitimate email I got every day. (Of course I still never suggested that email was broken.)
I was using Apple’s Mail.app, as well as Thunderbird, which both do spam detection, and running SpamAssassin on the server, and spam was still getting through, but I could live with it.
Then the bad thing happened, which was the server being pretty much brought to it’s knees (does a server have knees?) due to so much damn illegitimate email coming in, and SpamAssassin trying to deal with it all. The load went from less than 1 up 50 at one point. (We turned off SpamAssassin just to make the server functional.)
The solution? Greylisting. Suggested by Mr. Meister, once we implemented greylisting, I saw the amount of spam I got in a day go from 140 to 25. (Remember, we turned off SpamAssassin, which probably cut that 140 down a bit, but nowhere near just 25.)
So now we might not even turn SpamAssassin back on. We’ll have to determine if it’s worth the added load to deal with the fairly small amount of spam we get now. But as of today, email is working pretty good around these parts…