In many cases, it is the key in a hacker's tool kit, figuring prominently in most damaging virus attacks. File types can be disguised, however. In this case, the author used a feature in Microsoft's Outlook Express email program that conceals the true nature of Windows Shell Script Object files. This got people's attention because it appealed to them on some level. One person who clicked on an infected Stages attachment said it looked like a joke from someone he knew who often sends similar messages, Gullotto said.
Viruses frequently rely on humor.
Sex also sells. He asked readers not to share the file with anyone else. Apparently the virus writers had a better sense of human psychology than I do. Money has proven a less successful means of enticing people into opening infected files. People are very concerned about things like privacy and Internet fraud.