Spam messages are mostly represented by advertisements. Spam are usually sent in bulk and the recipient addresses are obtained by illegal means (e.g. by tapping the network communication). In their wilder modifications, spams may also distribute and seed dangerous viruses.
Kerio Connect contains a sophisticated antispam filter. The filter is designed so that it can recognize specific attributes of spam from the message contents (spam messages usually contain specific keywords that can be recognized and counted by the filter). Each message is assigned a numeric score; if this value exceeds the limit set in Kerio Connect, the message is marked as spam.
The spam filter may let some spam messages through from time to time by mistake (their score is low) and mark some regular messages as spam (their score is too high). For the reasons above, the antispam filter allows modification to the database used for recognition of spam messages. This method, however, requires user input. Users have to reassign the incorrectly evaluated messages to correct types (spam / non-spam) so that the filter learns to recognize them in the future.
Messages which were marked incorrectly can be re-evaluated by moving them in corresponding folders. To be specific, to mark a message as spam, move it to the Junk E-mail folder. To mark a message as not spam, move it to Inbox.
In MS Entourage, messages marked as spam are also marked by specific visual signs. For example, the line representing the message has a different colour (grey). However, these methods of spam-marking are not applied to messages moved manually. Such messages are distinguished as spam or not spam correctly by the server, but they are not changed visually. This implies that messages marked as spam are still displayed as spam and also displaying of messages marked as non-spam is not changed by moving them in the Junk E-mail folder.