K9 works with your regular POP3 e-mail program. It automatically classifies incoming e-mail as spam without any need of maintaining multiple rules or regular updates. It uses an intelligent statistical analysis with high precision. K9 is able to learn, and improves all along by processing more and more messages. K9 is designated for standard POP3 e-mail accounts only. It does not directly support web-mail services such as Hotmail or AOL, nor does it support SSL based security. The program comes in a variety of installer packages according to user's needs. There is no charge for using the software.