IBM SPAMGURU on the TREC 2005 spam track

IBM Research is developing an enterpriseclass anti-spam filter as part of our overall strategy of attacking the Spam problem on multiple fronts. Our anti-spam filter, SpamGuru, mirrors this philosophy by incorporating several different filtering technologies and intelligently combining their output to produce a single spamminess rating. The use of multiple algorithms improves the system's effectiveness and makes it more difficult for spammers to attack. While our overall performance was strong, our results did uncover some flaws and weaknesses in our existing implementation. Our latest code, with these weaknesses addressed as well as other enhancements, produces results on par with the best performing classifiers reported for TREC 2005 on the public corpus.