Map Shows Where People Are Voting on Election Day in Real Time

Facebook collects data about who cast their ballot.

— -- Think of it as the modern day equivalent of an "I voted" sticker.

So far, it appears that most people are voting -- or at least clicking the "I voted" button on Facebook -- in the Northeast, particularly around New Jersey, according to the map. But that could change as it gets later and the West Coast starts heading to the polls.

More than 4 million people have clicked the button today, Facebook said.