Heuristic analysis is the scoring of the message body allows a site to specify weights to each test for a specific spammer trick such as:

• Invisible ink where the font color closely matches the background

• Tiny text where the font size is so small that it is not visible

• Obfuscated URLs

• Random tags

and more.

A score is computed for the entire message and if this exceeds a threshold determined by the administrator, the message will be tagged as spam.