How well do those online voter registration campaigns work, really? Better than you might think. Both officials and the Center for Election Innovation & Research report that Facebook's four-day voter registration campaign, which sent friendly 17-word reminders starting September 23rd, triggered spikes in registrations across the US. These weren't just moderate bumps, either. Sign-ups in a given state grew anywhere from double to 23 times what they were on the 22nd, sometimes adding tens of thousands of voters.