Spam is unsolicited commercial email, the electronic equivalent of the junk mail that comes to your mailbox.

Spammers often disguise their email in an attempt to evade anti-spam software.

More than 99% of all spam comes from compromised computers, infected machines that are part of a botnet. Spam is often profitable: Spammers can send millions of emails in a single campaign at a negligible cost. If even one recipient out of 10,000 makes a purchase, the spammer can turn a profit.

Does spam matter?

  • Spam wastes staff time, Users without anti-spam protection have to check which email is spam and then delete it.
  • Users can easily overlook or delete important email, confusing it with spam.
  • Spam, like hoaxes or email viruses, uses bandwidth and fills up databases.
  • Some spam offends users. Employers may be held responsible, as they are expected to provide a safe working environment.
  • Spammers often use other people’s computers to send spam.
  • Spam is frequently used to distribute malware.

Spammers are now also exploiting the popularity of instant messaging and social networking sites such as Facebook and Twitter to avoid spam filters and to trick users into revealing sensitive and financial information.