To pull off the Small World Experiment, Yahoo is asking for help from the the nearly 750 million Facebook users.
Any Facebook user can sign up to participate in the experiment. The experiment tests whether anyone in the world can get a message to anyone else in six steps by passing the message from friend to friend.
The experiment starts with a sender, or a person at one end of the chain. The sender is then given a target to reach in six or less steps.
The target also volunteers some information such as work history, schools attended, place of residence, name of spouse and age.
After viewing the personal information, the sender chooses one Facebook friend to start the chain. Anyone can choose to become a target after completing one sender transaction. Targets will fill out an additional questionnaire, which the sender will use to reach the target.
Duncan Watts, principal research scientist for Yahoo Research, will direct the study.