Tom and Sputnik,
I'm a mail server administrator. We use blackhole lists for known spammers as well as Bayesian filtering to eliminate spam based on known wordlists.
Our antiviral software blocks 18,000+ viruses from spoofed email addresses every day. The number of spam messages that filtering blocks dwarfs that. This is for a company of only 50 people.
If only 1% of all spam makes it through the filters, that is still an unacceptable amount of garbage filling peoples inboxes.
There are many ways of bypassing filters, despite what you think. Email spoofing, the method of disguising the origin of an email is easily done at any server that does not have the proper safeguards in place. There are literally hundreds of thousands of these servers worldwide. In Asia and Russia, where there are no measures to regulate spam in place, some companies farm out servers to spammers for a fee. One of these servers can serve out over 80 million spam messages in a single day.
For a small company that pays for metered bandwidth, spam email can account for several gigabytes transferred each month. Whether you filter it or not at the server, you still have to receive it first, and that's another expense.
In the case of North Florida Zoological, there was no attempt to mask who they were, so if someone desired they could filter or block them out.
The typical spam email that you receive is distributed by a third party, and directs you to purchase though an unidentifiable website, phone number, or by responding to a drop-box email on an anonymous provider. You may receive the identical email 30 times, and it will appear to come from a different source every time. If you block by the sender, it doesn't matter. Chances are that the sender was randomly generated by a script. Blocking them won't stop the next one, as the sender will just be another generated name. Blocking the IP is pointless as well, when a typical server is only used for a day or two before they hop to another server with a different IP.
Bayesian filtering, which creates word lists based on messages you mark as junk, worked for a time but spammers are finding their way around that as well. If you've received any spam lately with a hundred or so random words attached to the bottom of it, that's intended to create "white noise", diluting the effectiveness or a word based filter.
The most insidious and evil aspect of spamming is the newer worms which have spread across millions of machines worldwide. They install relay servers on users machines without their knowledge. Click on an attachment and suddenly you're infected, and sending out 100,000 emails a day from your cable connection, and don't even know it. Some of those worms not only turn your machine into a spam relay, but steal form information from websites and files from your hard drive. There have been several suspected links to organized crime sponsoring the creation of some of these worms. Identity theft is skyrocketing, and it's just getting easier as people click on any email that comes in. Use Outlook 2000 or Outlook Express? Just clicking on an email to delete it in some cases can infect you, due to security holes in the mail client.
And this is all just the tip of the iceberg. So, as you may start to realize, spam is more than just a minor annoyance for many people. It's an intrusion into their daily work and time, and sometimes affects their personal lives directly.
And people who are offended that their email addresses are possibly being distributed without their consent have a right to be pissed. The shouldn't HAVE to sit there deleting messages every day just because they have an address. Would you like to have your phone ringing every 30 seconds all day long?
