Viruses:
A virus is a computer program that operates by piggybacking
on other programs. Any time the other program is run, the virus
is activated and able to do harm. Viruses can cause email addresses
to replicate themselves and send emails to anyone on your address
list. A famous example of an email virus is the Melissa virus
– the fastest spreading virus ever. When the attachment
was opened, the virus automatically spread itself to the first
50 emails in the address book. The most amazing thing is it
was only because of human error in opening the attachment that
it spread in the first place.