If the victim is a woman, a first guess is her first or middle name because it's common to namedaughters after grandmothers (the same holds true for sons and their male ancestors). Believe it or not, according to some security experts, would-be thieves will even figure out the victim's approximate age, guess backwards to estimate a date range for when her grandmother was born, and then go to sites like http://www.ssa.gov/OACT/babynames/, which list the most popular first names in a given year. Statistically, they will hit enough answers correctly to make it worth their while.
By Michael Copeland, senior writer
NEXT: Pet names