Here's a little info about my own email server back 2006:
I pulled my email logs for last week. For a period of 168 hours (7 days), there were 7153 attempts to deliver email to my server. 4888 were rejected due to DNSBL (thanks www.spamhaus.org); another 1159 were bounce'd, no such user. 254 connections ended in timeouts (most were from cnet.com); 6 were rejected due to relaying. The remaining 670 email's made it to my client, where 567 found there way into the SPAM folder.
In summary, out of 7153 attempts to deliver email to my server, only 128 were for legitimate email.
Since the Cakewalk forums are very well known and popular, I would imagine the numbers here 10x more than what I just listed. I've run forums in the past, it's a lot of work. I would say it is like recording a piano, with the monitor speaker inside the piano aimed at the mic.
I watched a forum get so overrun by spam it had to shut down. It was a good forum. I'm also a member of several closed forums. It keeps the riff-raff out, but it's a lot of work for those that run it.
I was looking at purchasing a product and had to registered with a forum to check it out, I moved on.
With all this talk about spam, y'all made me hungry...
-JJ