Debuted: May 2000
Origin: Philippines
Access method: E-mail attachment
Identifying trait: "I LOVEYOU" in subject line; attachment labeled as a love letter.
What it did: Replicated itself, sending copies to others. Also overwrote, modified and moved files; forwarded data (such as passwords).
Scope: About 3.1 million computers affected**
Cost: About $9 billion***
Postscript: Followed by at least 50 variants. Suspect identified; legal loophole resulted in dropped charges.
** "Guinness Book of World Records" estimate
*** VeriSign Inc. executive's testimony to U.S. House of Representatives telecom subcommittee, 2003