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The Fight Against Spam, Part 3

by FJ de Kermadec
05/21/2004

Editor's note: In part one, F.J. focused on laying the foundation for an anti-spam strategy and he covered how to block most of your unwanted mail. Then in part two, he fine-tuned this strategy, plus he took a closer look at the technologies inside of Mail.app. Now in part three, the conclusion of this series, F.J. covers rules and additional tools and techniques you can use to avoid becoming buried in spam.

Rules: When Junk Mail Is Not Enough

Many email applications base their spam filtering primarily on "rules." Luckily for Mac users, Mail uses more advanced technologies. However, let's not forget that rules do exist in Mail and that they can be extremely useful--especially since they can take advantage of AppleScript.

To add a rule, use the Rules preferences tab. Unless you've already added a few, you should see only one, from Apple, that adds a light blue color to mail it sends. Feel free to remove it if you want; it won't hurt your computer or prevent Apple from sending you messages.

To add rules, click on the "Add Rule" button. This will bring up a sheet on which you can define the conditions and the actions. Pay close attention when defining conditions to avoid flagging mail that you do not intend to flag: "Any" and "All", "Contains", and "Is" have very different meanings and results with regard to mail rules.

Finally, make sure you give your rule a meaningful name such as "Delete mail from Aunt Jane", and then click "OK" to save the rule.

One of the actions from which you can chose is "Stop evaluating rules." This action can be useful at times, but it can also interfere with regular email processing and slow performance. Avoid overusing it if you can.

The rule list itself has some useful functions. By grabbing rules with your mouse and dragging them up or down in the list, you actually can change the order in which Mail applies them. The rule in the first line will be applied first and the rule on the last line last, unless you have a "Stop" action in there somewhere. The positioning of rules can radically change the way your mail is processed.

Rules to Avoid

You may see rules on some sites about how to delete messages using a specific language or charset. Sure, this can stop spam coming from certain areas of the globe where this specific charset is commonly used, but it will also stop legitimate emails, therefore greatly increasing the risk of false positives.

Rules are an entirely automated mail processing system and, like all logic-based computerized systems, they require you to be extremely precise. Rules that are defined too loosely are more likely to catch mail that you wouldn't want them to catch. In some cases, especially if you trigger some kind of quarantine or deletion process, it is better to have false negatives than false positives.

A common complaint about rules is that they cannot bounce mail. However, for reasons that we will see in a second, this is actually a good thing and was probably done on purpose by the Mail engineers.

Interesting Rules to Set Up

Suppose that you are receiving an O'Reilly newsletter every month and that Mail constantly flags it as Junk Mail. You can set up a rule that checks the origin of the mail and flags messages coming from O'Reilly as "Not Junk" automatically. That way, you won't have to waste time on training the filter about this specific newsletter and can focus on more important and troublesome issues.

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Keep in mind that, by using the "Any" condition, you can set up a rule that un-flags promotional mail from the companies you like. Of course, Mail's spam filter is extremely good at distinguishing polite newsletters from real spam, so you probably won't need to create such a rule too often.

Responsible Behavior

Now that we have seen all the technical means by which you can effectively protect yourself against spam, it is time to look into the social ones. Indeed, most of the time, spam doesn't come from the ether but, instead, from a mistake we made at some point. Now, there's no need to blame yourself since everyone makes mistakes when it comes to spam.

As I recall, we left off with you having three email addresses and an unlimited number of dummy ones. Let's quickly review where we stand.

  • Your first address, the personal one, should only be given to people you entirely trust and whose computer or technical knowledge you trust too.
  • Your third address, the one you give to people you don't trust, should be spammed to a certain extent but, by applying the tricks we have seen and are going to cover later, you can keep things under control with minimum difficulty.
  • Your second address, the one you do business with, is in more or less the same situation. But, since you are a bit more cautious, spam is no way near interrupting the normal course of your business. A well-managed second address can, in fact, be almost spam-free.
  • Your dummy addresses (the ones you set up thanks to your forwarding account) come and go and that's fine since, thanks to mail forwarding, you keep them for five minutes at most before making them disappear--while ensuring that nobody can receive the spam emails that are actually intended for you since you are the owner of the domain name.

When you hear "be cautious", what do think I mean? How can you, in your normal online life, make sure that you are not making the infamous mistake that will cause spam to flood your inbox?

In the following paragraphs, you're going to see a few tricks that you can use to avoid spam--nothing too technical, but basic cautious advice that, applied carefully, should allow you to enjoy an almost spam-free email experience.

Don't Give Your Email Address to Everyone

It sounds silly but our email address is so often requested on the Internet that we rarely think of what we are doing when we provide it to someone. Therefore, before doing so, you should ask yourself: "If this were real life, would I give my address to this person?"

Of course, in most cases, your reply would be "No." So this might be a good time to provide your dummy address.

But what if the reply is "Maybe?" Well, there are a few things to ask yourself before you enter your second or third address, depending on the level of trust you have in a site:

  1. Do they publish a privacy policy? If not, back off. If yes, what are your rights?
  2. Is this site based in a country where the right to privacy exists; that is, is privacy clearly defined by law and enforced by authorities?
  3. Are there checkboxes somewhere telling you that you allow your address to be transmitted? If yes, make sure that you do not allow anything. If no, consider them virtually checked and back off.
  4. Does this site offer customer support or provide you with the guarantee that you can contact someone if something goes wrong? If no, be extremely careful and use your third address or a dummy one. If yes, test the customer support first with a general question. I have seen small, unheard-of companies reply to me in 15 minutes while big ones have taken 2 weeks to reply to the exact same question, so this really is an interesting check to perform.
  5. Do you know people who have already dealt with this site? If yes, ask them about issues they may have encountered. If no, use your third address or a dummy one.
  6. Is this company legally registered in its country and is it what it claims it is? If no, back off, no questions asked, and run as fast as you can.

Unless you can answer these questions, you should exercise caution. Sometimes, I create a dummy address for a specific site and monitor it closely. If I don't receive spam for a few weeks, I change my contact information so that the site knows the third address. If things remain stable, I enter the second one--but remember, never enter the first.

I know this checklist may sound a bit paranoid, but it is just the beginning of all the questions you should ask yourself.

Some companies are members of certification networks like the TRUSTe privacy program (of which Apple is a member, for example), which provides you with certain guarantees. TRUSTe is "an independent, nonprofit organization whose mission is to build users' trust and confidence in the Internet by promoting the use of fair information practices." Good networks have a "watchdog" system that allows you to fill out an unofficial complaint against a site in case they don't comply with their privacy policy. Keep in mind, however, that there are bogus certification networks and that privacy policies can be very "well" written, giving a site all rights to use your information without actually breaking any laws, so be careful!

Do Not Broadcast Your Address

If you have a site, or post on forums, or join a mailing list, you probably want people to be able to contact you--or the owner of the site may require you to provide a valid email address.

This is all perfectly normal, but you should still be cautious. Indeed, web pages and forums are now read tirelessly by spambots that desperately look for email addresses to steal. Mailing lists, by definition, expose your email address for the world to see--most of them at least. On some, only the postmasters know your address. These are usually called "*-announce" or have similar names.

Therefore, additional measures are required in these situations.

  • Do not type your email address into your web pages; use a form instead. If this is not possible, print your address into an image or hide it inside a JavaScript system. Creating a mailto link is like asking spammers to steal your address... See below for address masking tips.
  • When posting on forums, make sure that your contact information is not revealed. If you want to be contacted, use your third address or a dummy one in your public profile. Most forums provide you with checkboxes that allow you to chose which information will be disclosed. This is another good reason to visit your account preferences before posting your first message.
  • When posting in mailing lists, make sure that your address won't be revealed to other participants. If that is the case, use a specific dummy address. Nowadays, most lists' archives are protected against bots but it is impossible to know who has subscribed and what happens on their computers.

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