The notion of 'spam' designates any e-mail message that you never asked to receive. It is, essentially, a form of abuse, since these e-mails are unessential for the receiver. In modern times, the phenomenon has reached such proportions that almost one in two messages is spam.

Although there are many forms of spam (involving blogs, instant messaging or even mobile phones), the most frequent form remains, to this date, e-mail spamming. The reason why this tendency has soared in recent years is the fact that economically, it is a very cheap form of advertising. Numerous companies resort to this method, because all they have to do is handle a number of mailing lists, and it is quite difficult to hold them responsible as well as to implement anti spam techniques.

Implicitly, the receiving public has to cope with efficiency loss and time loss. Even e-mail service providers have had to raise the capacity level in order to deal with the extra-unwanted mail. Its costs are huge - the U.S. alone spent millions of dollars last year on lost productivity, and although cases are rare, there have been people who ended up in the court of justice over spamming issues.

Without an anti spam technique at work, any PC with a connection to the Internet is extremely vulnerable. Concisely, the purpose of anti spam software is to keep e-mail messages that you never required away from your inbox, by previously detecting them. After you install your anti spam program, it immediately filters all the e-mails that come your way.

This happens through a number of criteria for sorting out the emails. These criteria form the basis for the functioning of the spam filter. They comprise certain words in the subject or the content of the e-mail as well as certain types of files that come attached to the message, including special images. In addition, a spam filter allows you to see the address of the person, company or organization that sent the message in the first place. You can do this without actually opening the message, which is an essential feature - a large percentage of global spam messages contain viruses and other files that may be severely damaging for a computer.

Moreover, there is always the option of inserting a certain number of e-mail addresses into your spam filter - addresses belonging to people that you know and trust, who are utterly unlikely to send spam messages. In this manner, you are completely sure you will continue to receive messages from these people. The common attached to this process takes the form of your personal whitelist. In addition, there is the concept of blacklist as part of a spam filter. This includes a series of registered addresses known to send spam messages on a regular basis. The process is quite simple - if a message sent to your e-mail address comes from one of those addresses, the filter immediately rejects it.

Spam senders have gone to great lengths to refine sending methods, including everything from address harvesting to the message itself. In spite of all this, the point of a spam filter is to discern, as efficiently as possible, between wanted and unwanted e-mails, thus allowing you to receive legitimate messages without interference. This is essential as part of the security tools that protect you and your computer, so choosing your way to fight spam will undoubtedly save you a great deal of time and effort.