Automatic Learning

[shoodabean]

Hi, on this page

http://www.proxmox.com/cms_proxmox/en/products/mail-gateway/filtering-methods/

regarding this

 [B][SIZE=2]Autolearning [/SIZE][/B][SIZE=2]The system gathers statistical information about spam e-mails. This information is used by an autolearning algorithm, so the system becomes smarter over time.[/SIZE]

Can you expand on this please ?
What is the process ?
How does the system make it decisions ?

Thanks