I recently received an email from an online marketer who I made a purchase from. I was quite surprised to have received it, as it made two particularly bad mistakes that will often lead to email being diagnosed as spam, particularly if the recipient has quality bayesian filter software such as Spamwasher installed on their machine(luckily this message was sent to a webmail address as I doubt it would have got through to my primary email account). The first error was that I had never given the marketer permission to contact me. He merely took my email address from the purchase I made and added me to his list. This immediately classifies his mail as spam - it was unsolicited, he was mailing to a bulk list and the email was commercial in nature. I was prepared to forgive this as I did have a previous relationship with him. However maybe I was just in a good mood. A welcome email, with an opt-out link, or an opt-in email immediately after I purchased his product would have been far more acceptable. The second mistake is that he made no effort to identify his message. The subject line contained the generic words "Special Offer", both of which set off all sorts of alarm bells in any Bayesian Filter. I always enourage people to use an identifier in thier subject line, such as [STOPSPAMNOW]. This tells the recipient who the message is from as soon as they see it. As the recipient accepts the messages the identifier tag comes to carry a high positive Bayesian score(in other words your message is likely to be accepted regarless of content purely on the grounds that it has the identifier. It also makes it very easy for the recipient to set up a filter to deliver your message to a specific folder. The third, and most serious mistake, was putting all the addresses in the To: line. When you do this all your mailing lists emails are viewable by every individual member. The marketer has effectively just given me a list of people who have bought his product. Were I dishonest, I could easily add this list of people to my own list and have claimed a pile of easy sign ups. More concerning to me, anyone, or everyone else could do the same.

All these things are really just simple mistakes, but together they could easily add up to customers not getting e-mails, and bad faith from those who do.