Like you, I get annoyed at spam. But something happened to me a while back that not only annoyed the heck out of me, but also demonstrated that most people don't know how to properly deal with Spam.

First I got a new spam email, much like the other dozen or so I get each day. But then I started getting a bunch of angry emails demanding I remove them from MY mailing list. And then I got more emails from other people asking the angry people why the !@^#^! they were emailing THEM!

It seems that the bozo spammer in question had not only screwed up his spamming, but had left his email account set up so that any complaints were redirected to the last set of users he spammed to. The flood of email was most unamusing.

Because so many people were making fundamental mistakes in dealing with spam, I sent out an email to all the complainers explaining what had happened, along with some advice about how to better deal with the problem. I got enough response that I figured it would be worth writing an article about it.

The #1 mistake people make

Never, ever, EVER, for any reason, should you ever email to complain about a spam to the SPAMMER. All you are doing is confirming that your email address is valid. There are bad guys out there who send out spams solely to collect the email addresses of the complainers so they can resell them! Asking to be removed from a spam mailing list is pointless in most cases because the mailing is a 1-time thing. So don't bother.

If you've got the time, complain to the ISP instead

If you want to complain about a spam, complain to the ISP that sent the email to your ISP for delivery to you, because either

(1) it originated with one of their users or
(2) it was relayed through their server, and they need to close down that security hole.

Figuring out which this is means you have to look at the email headers and know how to interpret them. Don't assume that because the spam appears to come from moron@aol.com that AOL had anything to do with it. If you don't have experience in interpreting email headers, you are better off not worrying about it; someone who does will do the complaining for you! And if you do, remember to be polite when complaining, as it will get faster action.

Don't waste time using "_nospam" email addresses

Many people are configuring their email software so that it sets their return email address as either blank or with something added to it (ie: if they are "bill@whitehouse.gov" it is set to "bill_nospam@whitehouse.gov") They seem to think this will protect them from spam. It won't. Spammers are quite good at extracting the real email address (usually it is in the email headers anyway). All this trick does is inconvenience everyone who actually has to reply to your emails. They now have to manually edit your email address. And if they don't notice, the email bounces. It's annoying to everyone but the spammer!

Don't use autoresponders

Many new internet users use autoresponders to send a quick "I'll answer your email as soon as I can" response when they get an email. There are three reasons why this isn't a good idea:

It confirms to a spammer that your email address is valid.
Under certain circumstances, two autoresponders can get into a loop and continually send emails to each other!
And most importantly, it isn't necessary. The default expectation for an email is "I'll try and answer it as soon as I can." You don't need to tell people this. Autoresponders should only be used when you can't promptly answer your email, such as when you are shipwrecked on a small desert island with 6 fellow castaways.

So how can you reduce the annoyance of spam?

Bottom line, you've got several options. First, you can maintain 2 email addresses, one "public" that will get spammed, and a private one that you only give to people you know. Second, you can set up filters in your email address that attempt to detect the spam. The problem with this approach is that if it filters out an important email by accident, you might be in big trouble! The third approach is to just grin and bear it. My personal favorite, by far, is to use a good email application that supports filtering. You can easily filter out 95% of the spam you recieve if you know the tricks.

How to Filter Spam

If you do decide to implement some filters in your email, here's the crucial tip: Never use filters to automatically trash an email. Instead, use them to adjust the priority of your emails. I use (and highly recommend) the Eudora mail-client, and what I do is this: I use filters to mark email from friends and my favorite mailing lists as high-priority, and to mark things that look like spam as low-priority. Then I have my in-box set to display my mail in order of priority. That way, I can answer the important emails first, and when that's done, I can quickly look at the titles of the low-priority emails to see if there is anything I need to read.

Here are some handy filters that you can use to catch most typical spams:

First, since a lot of spammers are bombastically proclaiming that their email is sent pursuant to a new US federal law, a filter that marks any email containing the strings "SECTION 301" or "S.1618" works quite well.

Similarly, the following strings are often found in spam and rarely in legitimate email:

A subject line starting with "AD:", "ADV:" or containing "ADVERTISMENT" or "for free"
The strings "$$$" and "$MONEY$" The phrases "do not reply by", "believe it or not", "to order by phone", "to be removed", "?subject=remove", "email removal", "this is an important message", "received by mistake", "advertisement", "selected to receive", "direct email", "automatically been removed", "home business", "send check", "sending a check", "incredible details", "this system", and "from this mailing list"
And possibly most important, the phrases "one time mailing", "one-time mailing", "one time solicitation" and "one-time solicitation"! By the way, don't include a filter for the string "!!!". While this appears in almost all spams, it also appears in a lot of real emails.

Keep in mind that the order of your filters is important. Eudora has a particularly nice option in it's filters called "Skip Rest". You can set a filter so that if it matches, the filter is executed but no other filters are checked. So at the top of my list of filters are a set of filters that look for stuff I know I want to read (like my favorite mailing lists). If they match, they set the priority of that email to high, and stop filtering it. Next come my spam filters, and finally a bunch of other filters that do special things for me.

If your filter system doesn't have a "Skip Rest" feature, then you'll want to have your spam filters come first, then your "important email" filters. That way, if an email from your boss happens to get filtered by an anti-spam filter, as long as you have another filter that looks for your bosses' email address and sets it to a high priority, you'll never miss that email from him that reads "Believe it or not, we're giving you a promotion and a lot more $MONEY$!!!"

While not perfect, the filters described above will catch a lot of your spam and send it to the bottom of you in-box, and will very rarely make a mistake. As a test, I ran them on a sample of 5,000 or so emails in my trashed email folder; they caught almost all the spam, and didn't catch anything that wasn't spam (although, as mentioned above, I had other filters to filter email from known sources). I also ran them on a sample of 4,000 important emails in one of my saved email folders, and they mis-identified only 4 of them as spam.

Anti-Spam Intermediaries

Another interesting anti-spam technique is to use an intermediary service. These let you create temporary email addresses that redirect mail to your real email address. You give out the temporary email address to people whom you do not yet trust, and if ones of these email addresses appears on a spam list, you simply cancel it -- and you know who the leaker was