If you keep receiving multiple unwanted or spam messages, K9 can help you filtering them.
It acts as a bridge between your provider (POP3 server) and your mail client: when e-mail messages are going through it, they're being analyzed, and depending of their contents (keywords), are being automatically classified as being useful or spam messages. The information is pushed to your mail client in a customizable way (either by adding a keyword in the mail subject, a line in its header, etc.) on which you can rely to define a new filtering rule.
K9 learns to recognize spam messages very quickly and requires very few user interaction to build an efficient word database. From my own nearly 10-year experience, 490,000 "spam" keywords have been extracted on an average basis of 100 messages per day, for an overall accuracy higher than 95% on identified messages.
An excellent anti-spam utility for personal needs, rather stable, but which isn't being updated by its author anymore.
If you own several e-mail adresses and receive numerous messages, mainly spam, PopTray should interest you. It's an e-mail notifier which will keep you informed as soon as new mail comes to your mailboxes, and, most importantly, without downloading the message contents on your computer, thus avoiding viruses and other threats.
Associated with some anti-spam software such as K9, it can act as a first filter for unwanted messages, even deleting them if you want to, as it can apply rules and filters on the messages you receive as any usual client mail software.
But it is mainly focused on mail notification: it can check all your mailboxes at once, regularly (interval can be customized on each individual mailbox), notify you through a visual or audio alert, enabling you to check the messages and even delete them, before grabbing them into your mail client. It can also be used as a central point for all your mailboxes in a single interface.
A very good addition to your mail client, relatively light, although suffering from some bugs (mainly on international mail encoding) and lack of updates for many years.
By Renier Crause - Free (Open-Source) - Language: - http://www.poptray.org