Mark's Blog

I haven't blogged for a few days so I'll write few words about Spammunition, a Microsoft Outlook plugin for (surprise!) catching spam. Spammunition is still in beta, but I've been using this program for the last three weeks or so, and aside from a couple of bugs (which I emailed the author about) it's behaved very well and caught a large percentage of my spam. It can also function as a sort of mail-filtering tool for those office emails that are deleted half a second after they are opened.

Spammunition uses a Bayesian filtering approach, which uses statistics to calculate the probability of a particular email being spam, based on the words that appear in that email, and the probability that those words are in either known spam emails or known non-spam emails. Spammunition is remarkably accurate after very little training. If it all sounds a bit technical, let me assure you that you never need to know what is going on in the background in order to use the software. The concept for the software was originally from the much-quoted article by Paul Graham, A Plan for Spam.

Spammunition has some very neat features, including a "Show Analysis" option, which shows you the probability that the software thinks a given email is spam, and also shows you a list of the most interesting words in the email, for the purposes of spam detection. There is also a subject and email address whitelist so you can ensure that certain pieces of mail do not get filtered out. In practice, however, this has not seemed at all necessary.