Our century is famous for incurable maladies such as AIDS, cancer and spam. Mentioning unsolicited e-mails alongside with AIDS may seem ridiculous and even scandalous but nobody can argue that unwanted e-mails cause nowadays more headache than anything else and present a real problem.
Spam and diseases are far more alike than it seems at first sight. Internet "scientists" and "doctors" are obsessed with finding a vaccine against spam. It is not an exaggeration. The pace of life is getting faster every day. Time costs money. So why should one patiently wait for all unwanted e-mail to be delivered to his or her computer and then with the same patience sort them out? In reality there are a number of precautionary measures that are really easy to follow. However, strict discipline and no reductions are required. In the war against spam there can be no indulgence.
First, be careful. This means you should never leave e-mail on sites, at Usenet news groups, conferences or chat rooms. This is the main source for spam harvesting. E-mails are collected and put together on long lists then widespread by spam brokers. Such list or a CD can be obtained then by a spammer for a couple of dollars. The same refers to registering at sites. Net veterans advise to create an alternative (or temporal) e-mail - in case of a problem all spam e-mails will be delivered there leaving the main one healthy and free. This is much easier than notifying everybody of an e-mail change afterwards.
Second. Never answer spam e-mails. There is often a proposal to "unsubscribe if the e-mail is unwanted". A cheap trick. The only aim is to check whether the e-mail is a real one or not. Thus, answering such letter you register your name in a spammer list for good and all. There is no warranty that, following the instructions above, one will never get unsolicited e-mails. Spammers often use dictionary (or trial-and-error) method to make their lists. That is why the main struggle is led on the level of servers and computers already receiving spam.
Software companies develop programs defending a user from spam. Such programs are based on the idea of filtering and could be divided into two large groups: the first one filters e-mails by their content; in the other case the program is to define whether a sender is a spammer or not using so called Black Lists (spammers IP addresses lists) supported either locally or on the server. Black Lists method is rather widespread but not really effective: it takes time to enlist all spammers that keep acting looking for new computers and e-mails. A more efficient way to get rid of spam is a so called taught system that uses statistics to define by the e-mail content whether to treat it as an unwanted e-mail or not. The level of warranty is higher though such software is not free. An average price is $25-$40. Patience is in great demand - which is why people prefer to pay to get rid of spam.