Most email messages sent around the globe these days are spam, i.e. unasked-for messages with various offers or with links to malicious software. Not only are such emails irritating, but they also present a risk to your own computer, not to mention that you may get duped. That is why, many mail service providers rely on email filters, which are software apps that monitor all incoming emails and filter out the undesirable ones based on their content – what words an email consists of and how often they are referred to, what website a certain link opens, what outbound SMTP server the email is sent from, and so on. Some companies also rely on the databases of spam-tracing organizations devoted to providing the most up-to-the-minute info about undesired messages, to ensure that their customers will not receive any email message in their inbox that should not be there.