Spam filters are programs that analyze each incoming email message to determine whether the message is spam. If the filter decides that the message is spam, it reroutes the message, either to the recipient’s Junk mail folder. Spam filters scan the subject and body of the email, looking for words or phrases that are known as spam triggers or watch words, to determine whether a message is spam. Filters can also analyze the email header and the number of people on the distribution list. Many of the more sophisticated filters use a point system, in which the spam filter identifies words, phrases, or techniques commonly used in spam and assigns a score to each. Even if an email message doesn’t contain a blatant spam word or phrase, it can contain enough words that earn spam points to be filtered out and not delivered to the recipient.