Every election season Republicans and Democrats tried to rally their base and to go after undecided voters. They're increasingly using the Internet in Get Out The Vote efforts.
NPR correspondent Shankar Vedantam, who reports on social science research, joins me now to talk about how Facebook could become a potent weapon in going after the biggest untapped voting bloc in the nation. Shankar, welcome.
SHANKAR VEDANTAM, BYLINE: Hi, Melissa.
BLOCK: Who are these mystery voters, this untapped voting bloc that we mentioned?