A spam filter is a software application that is installed on a POP3/IMAP mail server and ‘scans’ all inbound messages to obstruct any unrequested ones from entering a particular inbox. A few instances of such email messages would be: offers for pills or money, false banking notifications or attachments that contain malicious software sent with the intention to damage your computer. Spam filters usually ‘scan’ the content of an email and when they spot given keywords or other dubious content, they either erase the email message or re-send it to the Spam/Junk folder instead of the Inbox folder. Some web hosting companies mix their own spam filters with up-to-the-minute databases from spam-monitoring organizations, so as to guarantee better protection for their customers. Such databases contain patterns, email server IPs and other info about spam email messages recently detected by these organizations.