The good news – Cloudmark has a spam filter which is free for consumer use and which uses collaborative filtering. If you receive a spam, you indicate it as such and a master database is updated so nobody else has to receive it. The bad news? It only works at the moment with Outlook, which is more prone to spreading viruses than other email software and I therefore avoid.
Is there any free Windows software out there that works reasonably well to stop spam that anyone out there can recommend?