1. A method for identifying and marking spam e-mails at a server, comprising: assigning a weight to each of a plurality of e-mail address categories, wherein the weight is based on a probability that an e-mail address category has been captured by a spam sender or a spam address catching program; determining a set of similar e-mails from a plurality of e-mails sent to the server; calculating a score for the set of similar e-mails, wherein the score is calculated by adding a plurality of weights, each of the plurality of weights corresponding to an appropriate e-mail address category for each e-mail in the set of similar e-mails; placing the score in the header of each e-mail in the set of similar e-mails; determining whether the score exceeds a threshold; and responsive to determining that the score exceeds the threshold, filtering the e-mail.