SpamShield Pro calculates a SpamShield Score for every message it analyzes. The higher a message's SpamShield Score, the more likely it's junk email.
SpamShield Pro assigns points to a message for suspicious indications of spam such as having "ADV" in the subject line, and reduces points for characteristics of legitimate email such as having a valid sender. On average, a message with a cumulative SpamShield Score greater than 3 is most likely junk email.
You can customize the maximum SpamShield Score that a message is allowed before SpamShield Pro considers it to be spam by adjusting SpamShield Pro's Sensitivity.
Some other things to consider other than the Sensitivity is the order of operations when a message enters the Everyone.net network.