Frequently Asked Questions
Q1: What is the spam score, and how is it related to the probability that a message is spam?
A1: Messages that go through our spam filter will get a "spam score", which is a number between 0 and 100. The higher the number, the more likely it is spam. A score of 0 is zero probability (according to the filter). A score of 100 is 100% probability, and a score of 50 is 50% probability. So why don't we just call it probability and be done? The problem is that if you look at "raw scores" coming out of a spam filter, you see a very uneven distribution, with most of the messages being near either end of the scale. Most users don't care about raw scores, or even probabilities. They just want to see a certain fraction, say the "best 10%" of the spam in their "unsure" category. So we have "stretched" the scale to make it easier to use and independent of whatever filter we are using. If you want to tag the best 10% of the spam as "unsure", set your ham/spam thresholds to 50/55. Note: This scale stretching is based on the spam score distributions for all users. Your individual distribution may be different, so this is only a rough guide. Use the wide default margins to start, and adjust them as you get more confidence in the filter.
Q2: Why do you clutter our subject lines with spam-score tags? Your authentication headers have all the info we need.
A2: Some email programs, like Outlook Express, are not able to interpret our header lines. Users of more sophisticated programs are more likely to adjust the options to their liking, so we made subject tagging an "opt-out" option. Go to the options-setting page (under Login) ***, and you will see how to turn this OFF. Hey, at least we don't obliterate the whole subject line with tags like ***[Possible UCE]*** I actually prefer to leave the tags ON, and keep the [*] and [**] messages in my inbox, sending only the [spam] to my spam bucket.
Q3: I'm mad as hell about spam, and all this sorting and tagging isn't much better than what I had before. Why can't you just block all the spamming domains right now? We all know they could stop outgoing spam if they wanted to.
A3: There have been many attempts, all failed, to whitelist all the good guys, and blacklist the bad. The key difference in our approach is that we are turning up the pressure slowly, and avoiding any hurdles, like making senders pay a big fee, or expecting them to adopt a particular method. We provide the tools. You and a million other recipients apply the pressure. We follow your policy on which senders will bypass the filter, and what fraction of the remaining mail will be rejected. Set your thresholds high, and senders will hear from their own customers. Soon they will discover that stopping spammers forging their name wasn't so hard after all. Be patient. We haven't yet reached the "tipping point" when all legitimate senders will feel the need to authenticate their outgoing mail.
Q4: This authentication stuff is working great, but still some of my mail is going through the spam filter. How long will it be before the spam is gone?
A4: It is unrealistic to think that spam will go away completely. I prefer to think of having a "clear channel" and "everything else". A better way to phrase the question is - How long before we can ignore the "everything else? That depends on your needs, of course, but I'm guessing that within a year almost everyone wanting to send me an email will know that they have to use a reputable sender. For me, that is B-rated, or better. I need to receive emails from strangers, and I can tolerate 10% spam in my inbox. Small domains seem to be having no problem offering authentication, and joining the "clear channel". Some of the larger domains are dragging their feet, for various reasons, including a belief that what we are doing is somehow contrary to their "business model". This is a situation much like the early days of email, when the large ISPs would not exchange emails with each other. Eventually, the community of little guys was bigger than any one big guy, and the big guys had to give up on their ambitions to monopolize the email market.