ABSTRACT
In general, spam refers to any unsolicited information that is received, often with topics related to money, pornography, or health. A European Union study in 2001 estimates that the worldwide cost of spam to Internet subscribers could be in the vicinity of US$10 billion per year. A recent study from the Ferris Research Institute [1] estimates that in 2007 spam will cost US$100 billion worldwide, with US$35 billion in the U.S. alone. The same study also mentions that the percentage of spam messages sent daily is greater than 75%.
