Mainsleaze is nerdy slang for spam sent by large, well-known, otherwise reputable organizations. Although the volume of mainsleaze is dwarfed by the volume of spam for fake drugs, account phishes, and Nigerian 419 fraud, it causes work for mail managers far out of proportion to its volume.

The new MainSleaze blog at http://mainsleaze.spambouncer.org/, run by long time anti-spam activist Catherine Jefferson is all mainsleaze all the time, and she’s having no trouble finding plenty of examples.

The problem with mainsleaze is that it is generally mixed in with mail that the recipients asked for, and there’s no way to tell the difference mechanically. Since it is legal in the US to send spam until people tell you to stop, although it’s against the terms of service of every ISP in the country, poorly informed or ethically challenged marketers beef up their lists by buying lists or by e-pending, trying to guess the e-mail address of customers for whom they have other contact info. Or sometimes, they decide to reactivate lists of addresses so old that some of them have been abandoned and later reassigned to other people.

As a result, if a mail system filters out all the mail from a mainsleazer, they’ll get complaints from the people who signed up. If they don’t filter, they’ll get complaints from the people who didn’t. Most mainsleaze is CAN SPAM compliant, so if you tell them to stop they generally will, at least until they buy another list with your address or e-pend it from someone else.

One ray of hope is the new Canadian anti-spam law, now expected to come into force in early 2012. It requires that commercial e-mail be sent only to recipients who have asked for it, or who have a demonstrable existing relationship, that is, no mainsleaze. Any large mailing list in the US is almost certain to contain addresses that are delivered to mail servers in Canada, either of Canadians (many of whom do not have .CA addresses), or of Americans who use a mail service hosted in Canada such as Tucows’ hosted e-mail.

If a mailbox is in Canada, Canadian law applies, and the new Canadian law allows spam recipients to sue the sender, even if the sender isn’t in Canada. So mainsleazers who don’t clean up their acts are likely to be on the receiving end of some expensive lawsuits. With any luck, after a few settlements, they’ll start to get the hint.