Melissa Virus

Representing one of the first viruses to spread via the medium of email, the Melissa virus swamped corporate networks with a barage of email messages in 1999. When opened as an attached infected Word document, the virus would copy itself to the first 50 email contacts in the user's address book. Many recipients were fooled by the email simply because it bore the name of someone they knew and referred to a document they had allegedly requested.

As a result of how effective the Melissa virus was at replicating and spreading, it spread throughout the world within a matter of hours. In fact, so much email traffic was generated by this virus, and so rapidly, that companies like Intel and Microsoft were forced to turn off their email servers. The Melissa virus was the first virus capable of hopping from one machine to another on its own.