29. A non-transitory machine-readable storage medium storing one or more sequences of instructions for determining a reputation of a message sender, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps of: obtaining two or more lists from two or more list providers; determining which lists of the two or more lists indicate the message sender; extracting from each list of the two or more lists indicating the message sender an individual score for the message sender, representing an individual probability that the message sender sent an unsolicited message; and computing a reputation score for the message sender from the individual scores for the message sender from each list of the two or more lists indicating the message sender; wherein the step of computing the reputation score comprises determining an aggregate score based on the individual score for each list of the two or more lists by performing at least one of a Chi Squared calculation, a Robinson calculation and a Bayes calculation on the individual scores for the message sender.
29. A non-transitory machine-readable storage medium storing one or more sequences of instructions for determining a reputation of a message sender, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps of: obtaining two or more lists from two or more list providers; determining which lists of the two or more lists indicate the message sender; extracting from each list of the two or more lists indicating the message sender an individual score for the message sender, representing an individual probability that the message sender sent an unsolicited message; and computing a reputation score for the message sender from the individual scores for the message sender from each list of the two or more lists indicating the message sender; wherein the step of computing the reputation score comprises determining an aggregate score based on the individual score for each list of the two or more lists by performing at least one of a Chi Squared calculation, a Robinson calculation and a Bayes calculation on the individual scores for the message sender. 34. The machine-readable storage medium of claim 29 , further comprising instructions which, when executed by the one or more processors, cause the one or more processors to carry out the step of receiving a request for the reputation of the message sender.