‘Spam’ or ‘spam’ are terms used to name the email ads you did not ask and do not want. Note that the term Spam is somewhat broader than the ‘core junk’ because the ‘spam’, also includes other forms of aggressive advertising and illegal, such as writing in forums and newsgroups for advertising purposes. However there are some ways to protect and fight against this intrusion of privacy. Never respond to spam. Do not do it even to send a request to be removed from the mailing list. Most people who send SPAM does not consider these requests and, worse, add to other lists or validate their email address and as active and belonging to someone with a name: you. After validation, sell your address to those interested in databases and will continue to be, therefore, more SPAM.
To defend, you should complain to the service provider (ISP) that sent the message originated. The easiest way to report this abuse is to use certain programs such as SpamCop. This form of defense actually reduces the volume of spam received.