What is Mainsleaze Spam?
Spam is unsolicited bulk email: bulk email sent to an email address that did not request to receive that email. Mainsleaze spam is spam sent by an (otherwise) legitimate company or organization, either directly from their own IPs, through an external SMTP relay service to which they have legitimate access (such as SMTP.com or Google Postini), or through a legitimate email service provider (ESP).
Because of the difficulty proving that this type of bulk email was unsolicited, the usual anti-spam measures do not work well against mainsleaze spam. In many cases the same bulk email is sent both to email addresses that actually requested it and those that did not. Blacklists are reluctant to list the IPs and domains of legitimate companies and ESPs because they send a significant amount of legitimate, non-spam email. Reputation services usually rate these companies reasonably well because bulk email volumes are not huge, and most legitimate companies and ESPs use good bulk email sanitation and therefore rarely hit spamtraps. Whitelists often list the IPs of ESPs and legitimate companies. Mainsleaze spam is therefore much more likely to end up in the user’s inbox that other types of spam.
These factors make mainsleaze spam unusually annoying to many of its recipients. This blog intends to publicize that annoyance and hand it back to the company or companies responsible, in hopes that they will change how they manage their bulk email advertising and thereby quit annoying people with it.