In recent months, e-card spam infected with a virulent computer worm has increased. How do you tell the difference between a valid e-card and a virus? Never open a greeting card sent from an unnamed friend, neighbor, classmate, schoolmate, partner or family member. Two things to look for are whether you know the sender, and the kind of link they are asking you to click. Learn more about the Storm Worm at Information Week and this Chris Pirillo Video .