Junk Mail Controls
Both Thunderbird and the Mozilla Suite can detect and filter unwanted e-mails. In order for the junk-mail filtering to be effective, you first need to "train" it because it uses Bayesian filtering.
When you first get Thunderbird, it has default spam detection. Certain emails you do want may be considered spam, and others that you don't will not. Every time you mark an email you don't want as junk, Thunderbird's filtering will improve. When you specify that certain e-mails Thunderbird says are junk are not, it improves as well. Eventually, the accuracy rate will improve to be correctly identifying and junking 90% of incoming spam. In the first few weeks, hovever, accuracy may be poor, with many false positves. That means you should check your Junk folder regularly for "lost" e-mail until Thunderbird filtering becomes good.
Manual junk mail filters are also available under the general mail filtering rules, so you can specify that emails that fit certain precise conditions either are or are not considered junk. Whether Thunderbird or you specify that email is junk, your Junk Mail Controls settings, accessible under the Tools menu, control whether an email marked as junk is deleted, moved to the Trash, somewhere else, or whether nothing at all is done with them.
Most users, particularly those who are familiar with peer-to-peer spam fighting software (like Cloudmark's Safetybar for Outlook) will require patience with Thunderbird's bayesian filtering. Bayesian filtering alone is unlikely to be as good as P2P approaches. To date Thunderbird does not have an antispam application sufficiently accurate enough to "turn it on and forget about spam."
