Melissa is a virus that exploits the macro feature within the Microsoft Office suite in order to infect documents and mass mail copies of itself to a victims address book. Unlike viruses that are packaged as stand-alone executable files, Melissa uses a feature that allows Office documents to activate other Microsoft applications and use their abilities.

While it is true that there was a virus that appeared in the summer of 2007 with a subject line of, “You’ve received a postcard from a family member,” as well as several other variations of the subject line that talked about a “card” or a “greeting card,” these viruses had nothing to do with this false warning about “A card for you” or “A virtual card for you.”

W32 is commonly used as the prefix for many variants of viruses and worms that exploit vulnerabilities in the 32-bit versions of Microsoft Windows. The majority of W32 viruses and worms are spread online through network services including email, web sites, file sharing systems, and instant messages. Therefore, any computer connected to the Internet runs the risk of of being infected with a W32 virus.

The Merry Christmas virus is an email worm that started to emerge before Christmas of 2004. The worm spread via electronic mail as a small, executable file with a variety of names and extensions. The worm propagated by copying itself onto local and networked drives, as well as emailing itself as an attachment to any addresses it could harvest from the address book and files stored on the infected machine.

The Invitation virus hoax involved an e-mail spam in 2006 that advised computer users to delete an email, with any type of attachment that stated “invitation” because it was a computer virus. This is also known as the Olympic Torch virus hoax.

The Life is Beautiful hoax virus warns of an infected PowerPoint presentation. It has been reported in Spanish, Portuguese, English, German, French and Yugoslavian. This hoax warns of a deceptively titled message carrying an infected Microsoft PowerPoint file named “Life is Beautiful.” It originally circulated in Portuguese but was later translated into English and a host of other languages.

At its height, ILOVEYOU infected 10 percent of computers connected to the Internet, causing $5.5 billion in damage. The virus’s rapid proliferation is a result of its use of mailing lists, social engineering and VBScripts. Because the viruses generated targets based on the mailing lists stored on a victim’s machine, infected messages appeared to come from an acquaintance and were often considered safe as a result.