Spam (unsolicited/junk email) is an ever growing problem. Of the 30 billion+ emails sent every day around 40% of it is rubbish (around 12 billion messages!!) and this number keeps growing*. Most people delete spam as they receive it but cumulatively this costs individuals and businesses precious time and money. A common solution is to install a spam filter on either the client or server side. If properly configured these can be very effective although no solution is ever 100% effective as you are always balancing the chance of deleting genuine emails with blocking the maximum amount of spam. In the past I’ve have to ditch mail accounts which have become overrun with spam but have been lucky so far with my current addresses. I recently discovered that the mailbox of the root account on my mail server was getting bombarded with spam so took the step to install ‘SpamAssassin‘ which filters all incoming mail. It uses a wide range of advanced heuristic and statistical analysis tests on mail headers and body text to identify spam. It’s a bit difficult to setup as it requires you to fiddle about with Sendmail and Procmail but so far I’ve found it to be quite effective.
An engineer at Microsoft recently posted an interesting visual history of spam which highlights the growing problem well. Bill Gates has claimed that he’s working on a solution to the issue but I can’t see anything radical happening for quite a long time!
*Statistics taken from ‘Spam Filter Review‘ 2004.