Today there are many types of “electronic-spam”, including the most famous “E-mail spam” aka “unsolicited e-mail”, “Forum Spam”, “Newsgroup Spam” Advertisement and forgery in a newsgroup, “Messaging Spam or Spim” that is spam through instant messaging system for advertisement or even extortion. On the web, there is an important type of spam called “Spamdexing” – the art of manipulating a search engine to create the illusion of popularity of a particular website.
The University of Maryland issued a report in 2003, saying that spam costs businesses approximately $22 billion in lost productivity each year. There seems to be a no easy ways to deal with spam. Microsoft Chairman Bill Gates said in 2004: “two years from now, spam will be solved”. Well, that is another mis-prediction from Bill Gates.