The president's re-election campaign used targeted person-to-person contact on Facebook to reach five million voters, many of whom were the focus of an effort to reach 18-to-29-year-old voters who not be reached by phone, Obama for America Digital Director Teddy Goff said Friday.

Campaign officials have previously said that asking supporters to reach out to their friends had a high rate of success, but I hadn't heard a campaign staffer actually say how many people the campaign reached this way — until today. Goff and OfA Deputy Campaign Director Stefanie Cutter discussed technology, communications and the 2012 campaign during a taping for SiriusXM Left held at Rootscamp and set to air later on Friday. His remarks do more to validate the hype around directed, person-to-person Facebook contact, which may emerge as a new core technology in much the same way campaigns embraced online advertising and SMS messaging after watching those tools work in 2008.

The problem with GOTV targets in that age group is that half of them can't be reached by phone, Goff said.

But 85 percent(!) of them were a friend of a friend of Barack Obama on Facebook, he said.

"Facebook became the only place where we could reach them," Goff said.

"So we had about seven million instances of people contacting about five million people, all of their friends who they knew ... these were people we had to reach, and couldn't reach otherwise," Goff added later on.

Obama campaign officials have already said that 20 percent of people asked by their friends to register, vote or take another activity did as they were asked to do. Consultants I spoke with said that was all well and good, but the fact that the campaign was talking about rates rather than hard numbers suggested the number of people who were actually contacted was low.

Just shy of 1 million people had signed up for the Obama for America Facebook app as of election day. Goff said supporters reached about five million people through Facebook with seven million pieces of content. And it's already been well established that fewer young voters have landline phones while more people generally are communicating over the Internet, especially over mobile phones and on social networks.

So there you go.