Detecting spam email using multiple spam classifiers

A method of detecting whether a first e-mail is undesirable, the method comprising the steps of:

• inputting the first e-mail to a classifier;
• obtaining from the classifier a classification of the first e-mail, wherein a range of classifications includes a first classification indicating that the first e-mail cannot be classified as either spam or non-spam;
• and
• taking an action if the first e-mail is classified under the first classification.

A method for detecting undesirable e-mail, the method comprising:

• inputting a first e-mail to each of a plurality of constituent spam classifiers;
• obtaining at least one score from each of the plurality of constituent spam classifiers indicating the degree to which the first e-mail is deemed spam;
• obtaining a combined spam score from a combined spam classifier that takes as input the at least one score from each of the plurality of constituent spam classifiers, at least one of the plurality of constituent spam classifiers being a member of a similarity-detection family;
• and
• identifying the first e-mail as an undesirable e-mail if the combined spam score indicates that the first e-mail is undesirable.

A computer readable medium including computer instructions for detecting whether a first e-mail is undesirable, the computer instructions including instructions for:

• inputting the first e-mail to each of a plurality of constituent spam classifiers;
• obtaining at least one score from each of the plurality of constituent spam classifiers indicating the degree to which the first e-mail is deemed spam;
• obtaining a combined spam score from a combined spam classifier that takes as input the at least one score from the plurality of constituent spam classifiers, the combined spam classifier being computed automatically in accordance with a false-positive vs. false-negative tradeoff;
• and
• identifying the first e-mail as an undesirable e-mail if the combined spam score indicates that the first e-mail is undesirable.

An information processing system for detecting whether a first e-mail is undesirable, comprising:

• a processor configured for:
• inputting the first e-mail to each of a plurality of constituent spam classifiers;
• obtaining at least one score from each of the plurality of constituent spam classifiers indicating the degree to which the first e-mail is deemed spam;
• obtaining a combined spam score from a combined spam classifier that takes as input the at least one score from the plurality of constituent spam classifiers, the combined spam classifier being computed automatically in accordance with a false-positive vs. false-negative tradeoff;
• and
• identifying the first e-mail as an undesirable e-mail if the combined spam score indicates that the first e-mail is undesirable.