In the traditional scenario, it was an individual, highly technical and working alone, who would write a virus program and then introduce it onto a computer, network server, or the Internet. Why? Ego, revenge, sabotage, and basic disgruntlement are some factors that motivated these individuals.
Now, however, it takes no special skill to create a macro virus, a mass mailer, or other virus with highly disruptive potential. In fact, "virus kits" proliferate on the Internet and are free for the taking for anyone who wants to try their hand at disrupting the Internet or corporate communications.
And increasingly, organized crime from remote countries gets into the act by creating sophisticated spyware programs and phish sites. Distributed using a million spam messages, these exploits are low effort but with a high potential for yielding personal information such as passwords, social security numbers, credit card numbers, etc.