Bernie Sanders’ presidential campaign has surpassed President Obama’s in turning large numbers of people “who don’t normally engage in grass-roots politics into an advance team capable of doing everything from managing phone banks to planning high-level campaign events,” writes Nancy Scola at Politico.

As of early April, Sanders’ “tens of thousands of networked volunteers had made 47 million phone calls, putting them on track to surpass the calls made by Obama’s operation during the entire 2012 election cycle.”

Sanders’ organizational success — fueled by free or low-cost, off-the-shelf apps like Hustle and Slack — is the lesser-known counterpart to his campaign’s prowess in raking in campaign cash from hordes of shallow-pocketed donors online. Experts in the evolution of technology in political campaigns say these innovations have helped Sanders put up a far more vigorous than expected challenge to Democratic front-runner Hillary Clinton, including his 13-point win in Tuesday’s Wisconsin primary and his 12-point victory Saturday in Wyoming.

“Sanders’ team is investing a lot of time and energy into thinking how to do things differently, how to build a distributed operation that translates into dollars and volunteers,” said Daniel Kreiss, a former political organizer who wrote the book “Taking Our Country Back: The Crafting of Networked Politics from Howard Dean to Barack Obama.”

While Obama’s campaigns broke new ground in bridging the offline and online divide, “here the scale is different, the technology has changed, and every step along the way that creates greater scale, greater speed and lowers the cost of mobilizing a digital base in the service of electoral politics,” said Kreiss, a media professor at the University of North Carolina in Chapel Hill. …

Sanders’ virtual volunteers do campaign work that has traditionally been handled by paid operatives or fallen through the cracks in a busy election cycle — such as identifying likely voters or turning out people to campaign events.

The goal is to till the ground in primary and caucus states so that when Sanders’ paid staffers arrive, they can devote their attention to voters who aren’t yet sold on the 74-year-old democratic socialist.

“We’ve been able to engage people in voter contact no matter where they are in the world,” said Claire Sandberg, the digital organizing director for the Sanders campaign and a former anti-fracking activist. The volunteers are “running huge chunks of the campaign,” said Zack Exley, a Sanders adviser and veteran of MoveOn.org and Howard Dean’s 2004 White House run.