A harmless web link could end up being a costly Trojan virus. Zeus is a Trojan horse that uses key logging to steal banking information of unaware victims. The first incident was made aware in 2007 when information from the United States Department of Transportation was stolen. In 2009 Zeus become more prominent. The Zeus Trojan has targeted thousands of FTP accounts many of large well known companies including the Bank of America, NASA, Monster, ABC, Oracle, Cisco, Amazon.
Zeus only targets Windows operating systems mostly running XP Professional SP2. "That is good news for me as I run Ubuntu Linux and occasionally Windows 7."
According to news articles this type of Trojan is difficult to detect. Over 3.6 Million users alone in the USA are said to be infected.