K9 is an email filtering application that works in conjunction with your regular POP3 email program and automatically classifies incoming emails as spam (junk email) or non-spam without the need for maintaining dozens of rules or constant updates to be downloaded. It uses intelligent statistical analysis that can result in extremely high accuracy over time. K9 learns from its mistakes and becomes better and better at being able to identify spam. More importantly it learns to recognize what you consider to be spam. K9 is for standard POP3 email accounts only. It does not directly support Hotmail, AOL or any other kind of webmail type systems, nor does it support SSL or secure authentication as used by MSN.