Spam is unsolicited and unwanted email. Other common names of spam are spam mail, bulk email or just junk mail. Today, spam has reached such monumental proportions that almost every other message we receive is spam. Protecting the inbox with anti-spam filter has become one of the barest necessities for almost all PC users.

In a few words, anti-spam software helps detect spam. It is a program that detects unsolicited and unwanted e-mails, and doesn't let them slipping into your inbox. The anti-spam program is installed onto your computer and filters your inbound emails. The email filtering is carried out based on a number of criteria. These can be specific words in the subject line or in the body of the message, type of files attached to the message, images embedded into the message. You could set the filter to check the sender's email address out. If you have your own whitelist or address book with trusted email addresses, you could arrange the anti-spam filter to refer to that whitelist. It also can detect known spammers by checking a blacklist of habitual spam senders maintained by certain Internet Service Providers. If the email sender is on the blacklist, the message is rejected.

Anti-spam filters have adapted to the wiles of the spammers. They use techniques that do not trash legitimate emails by effectively analyzing the content of the email. Such software looks for keywords and tries to interpret their meanings in the sentences. Certain spam filters reject the messages if they come to you in the form of "Undisclosed Recipients", and accept the emails where your email address is in the “To” or “Cc” fields.

Anti-spam filter is an essential part of your computer's security tools if you want to ensure that you only receive the emails you want. Now you can select the right anti-spam software for your computer and start fighting spam.