Spam categorisation functions at Posteo with a points system, as it also does with many other email providers. Our spam filter checks every incoming email against various criteria and awards points. The most important of these are the sending server and technical criteria – the content is less important. If an email is awarded a high point score during this check, it will be classified as spam, and will not be accepted. If it receives a low point score, it will be accepted and delivered to the recipient.
What happens when an email is classified as spam?
If the filter classifies an email as spam, it will not arrive, and the sender will be immediately notified that it was not delivered. There is no such thing as a folder for “suspected spam” at Posteo.
Our spam filter is very effective and only incorrectly classifies an email as spam on extremely rare occasions. If this does occur, the sender is immediately notified (by their server) that our server did not accept the email. The sender can attempt to remedy the reasons for classification as spam or, alternatively, contact the recipient via a different method.
With this approach, we prevent emails from getting lost. “Real” emails are often ignored after landing in a “suspected spam” folder. In addition, some providers automatically delete the emails in the “suspected spam” folder after a short time. This is how emails get “lost” with spam folders – the sender believes the email was sent as usual and read, but the recipient has missed the email completely, as it is in the spam folder. After some time it is then automatically deleted by the provider.
Moreover, we chose to administer our spam filter centrally. The filter is not, therefore, trained by the users. We decided on this approach because users often mark newsletters, notifications and advertising as spam, even though technically, they are not spam. You have the possibility, in addition to our central filter, to set up your own filter for emails from undesired senders.