EcommerceBytes-Update, Number 85 - December 15, 2002 - ISSN 1528-6703     4 of 6

Spam Filters & Blacklists: Solution Worse than Problem?

By Yisroel (Izzy) Goodman

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In an effort to combat spam, people often use software programs to filter out unsolicited email. But sometimes these filters go out of control and are worse than the problem they are trying to fix.

Software vendors use different approaches in their anti-spam tools. Some, like Spamcop, create blacklists of spammers. If an email address appears on the blacklist, then any email from that address will be filtered out from recipients' inbox. This approach would work if vendors took more time and care in verifying their blacklists. But some vendors may add people to the blacklist based on one or two unverified complaints.

Many spammers use someone else's email address to send out their junk. Anti-spam vendors should have the common sense to understand this and do a little investigation before tarnishing an innocent person's reputation. And often, a subscriber to a newsletter will simply forget that they signed up for a particular newsletter and will report the newsletter as spam.

But the problem doesn't stop there. If someone is reported as a spammer, Internet Service Providers (ISPs) can block that IP address. An IP address might belong to an entire server with many sites on it. So if one person from a particular server is accused of spamming, everyone on that server may have problems sending legitimate email to the ISP that is blocking.Recently, one vendor went beyond this into an area that borders on censorship. They contacted the company that hosts my Web site and threatened to add their domain to the blacklist unless I was shut down for abuse. It took several emails back and forth before the actual complaint was revealed: I have a page on my site with tributes to the WTC heroes and anti-terrorist humor. An organization got their members to report me to Spamcop for abuse because they took exception to some of the content. So groups can abuse anti-spam tools to try and censor sites they don't like.

Another anti-spam tool is the email filter. Some servers set up programs to filter emails based on certain rules. If an email violates a spam rule, it is deleted as spam and never passed on to the recipient. An email might be rejected simply for containing a word that may not even be offensive.

For example, some viruses have gone out with the subject "A funny joke" and "I love you." Some email filters will now reject any email containing the words "funny," "joke," or "love"! A newsletter sent out by Symantec warning subscribers about new viruses was rejected because it contained the word "virus." And in a case reminiscent of Frankenstein, where the creation turned on its creator, emails from firms producing anti-spam tools were rejected because they contained the word "spam."

A good anti-spam tool (Mailwasher from, Cloudmark from does not work behind your back. It marks the message as spam and puts it aside, so you still have the option to read it. For those of you who subscribe to Spamcop or use filtering software, if you have stopped getting ezines to which you subscribed, or if you have discovered that you are "losing" emails, ask yourself if you really need someone else deciding what they will allow you to see.

About the author:

Yisroel (Izzy) Goodman owns Complete Computer Services Inc. and sells electronics and ink cartridges online. His Web site contains articles about creating web sites, using HTML and ASP, obtaining a merchant account, payment service ratings, and avoiding fraud. His informed opinions are based on his own experience and from reading about others' experiences with payment services as well as discussions with users, representatives of the services and experts in the field. (Note: He is not affiliated in any way, directly or indirectly, with any payment service.) He can be reached by email at

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