SpamPal

SpamPal is a free software application, capable of excluding spam from your mailing list. Thus, you can enjoy readying valid content. It is mainly oriented toward users with some experience in similar tools.
The interface of the program is based on a standard and uncomplicated window where you can set up a wide range of configuration options.
The app can filter POP3, IMAP4 and SMTP traffic, once you fill in account details. You can select the filtering strategy between safe, medium and aggressive, according to which level of protection is more suitable to your preferences.
SpamPal supports SpamPal Monitor (to easy keep track on the program service) and a URL body plugin (detects spam by looking at websites linked to/from a message). Furthermore, it can be enabled to assume that all mail from China, Korea and Taiwan is spam, as well as to use a RegExFilter plugin (filters or whitelists your email, based on Perl Regular Expressions).
In addition, you can create a whitelist, blacklist or ignore list, set message tagging parameters, make the app minimize to the system tray area and to automatically run at system startup, enable logging mode, as well as configure advanced options, among others (e.g. set the maximum simultaneous DNSBL queries, allow multiple port settings to share a single port number).
The application runs on a low quantity of CPU and system memory, has a good response time and worked smoothly during our tests, without freezing, crashing or popping up errors. There's is also a help file available. However; less experienced users would have a hard time figuring out SpamPal's features, due to its advanced settings. Unfortunately, no recent updates have been made.