Volunteers in Virginia for Mitt Romney's campaign wear red T-shirts that feature a digital code that voters can zap with their smart phones to learn more about the Republican presidential hopeful.

 

The volunteer "data captains" who staff President Barack Obama's re-election offices in Florida process reams of material generated by local phone banks that will be mined by the campaign's organizing teams.

 

Four years after the 2008 Obama campaign revolutionized the use of the Internet for fundraising and communication with supporters, both the Obama and Romney teams are using digital technology to streamline the labor intensive work of mobilizing voters in battleground states.