In the present, technology-driven time, working on computers and the Internet is indispensable. For those who work on the Internet extensively, spam is a huge annoyance. Defined as unsolicited e-mail, often of a commercial nature, sent indiscriminately to multiple mailing lists, individuals, or newsgroups, spam increasingly became a headache for net surfers, until spam filters came into existence.

Spam filters are software programs capable of identifying spam and blocking its entry into mail boxes. Whether Yahoo, Hotmail or any other web email service, all offer spam filters to help their members.

However, the threat of spam doesn't end here. Official mail services like Outlook and Eudora are not spared from spam entering via mail. Spam can further harm the system, as it may contain virus inflicted programs that may cause damage to the PC.

To combat spam, there are effective spam filters which are programmed to tackle and wash out all types of spam. Spam filters come in three basic categories that are often used in combination to stop spam.

Volume, frequency, and “bad address” filters are used to monitor the number of emails being sent in each flight, the time between flights, and how many bad addresses are included. Blacklist filters work on the basic information in compiled lists of domain addresses that have been identified as spammers by the major Internet service providers. Content-based filtering is generally considered the best and most effective spam filtering technique. The software blocks spam by monitoring words in the email text that may trigger the filter.

Downloading and using spam filters is extremely easy, and most of them do not require any extra software or hardware support. To meet the ever-increasing demand, IT professionals all over the globe are busy developing newer filters which can fulfill the requirements effectively.