A spam filter is a software app that’s installed on a POP3/IMAP mail server and keeps track of all inbound messages to hinder any undesirable ones from reaching a given inbox. A few examples of such emails would be: offers for pills or cash, fake banking notices or attachments that contain malware sent with the intention of infecting your personal computer. Spam filters usually ‘scan’ the content of an email and when they come across certain keywords or other dubious content, they either delete the message or redirect it to the Spam/Junk folder instead of the Inbox folder. Certain companies combine their own spam filters with up-to-the-minute databases from spam-tracing organizations, so as to ensure better security for their clients. Such databases contain patterns, email server IP addresses and other information about spam email messages recently uncovered by these organizations.