Facebook's map runs on autopilot: Load it up, sit and watch, almost like an iTunes visualisation. Blue dots show a polling place check-in, while a counter above tallies the total check-ins. The map can also be switched into an impressive full-screen view.
Facebook's voting check-in data can also be broken down by state, showing peak voting times and age/gender breakdowns.
Over on Foursquare's map, the premise is much the same: a live map shows check-ins by state, although it doesn't run automatically the way Facebook's map does.
Foursquare also has a special badge for Election Day. Anybody who checks in to a polling place gets the "I Voted" 2012 edition badge: