Last week's "filibuster" of the deal to raise the debt limit was widely seen as a bust for Sen. Rand Paul (R-Ky.). With great fanfare, one day before the CNBC presidential debate, Paul said that he would take the floor and make life difficult for the deal's backers "until we talk about proposals." In the end, he talked for less than two hours -- and Sen. Ted Cruz (R-Tex.) arrived to talk even more.

Then, to the Paul campaign's surprise, one video of his speech transformed into a hit. Sen. Mike Lee (R-Utah), a member of Paul's 2010 Tea Party class, shared the longest stretch of the Paul speech on Facebook. "I was proud to vote with Senator Paul on his point of order that would have protected Social Security, and I ask you to help me shine a light on what Washington has tried to hide from you in the darkness of night," Lee wrote. "If everyone who sees this message shares it, it will reach millions of Americans."

Paul's campaign had not uploaded much of the speech to its YouTube account; none of the clips that made it up got more than 3,500 views. But over two days, the Lee video got more than 19 million impressions. (By contrast, the most popular YouTube video posted by Cruz has nearly 600,000 YouTube views.)

"Virality means increased traffic, sign ups, and of course digital donations," said Paul's digital strategist Vincent Harris. "[It's] a huge number in a short amount of time by any standards, especially considering the fact the campaign didn't pay a cent to promote it. Seems to be the most 'viral' moment since the senator stood up for life against Debbie Wasserman Schultz in New Hampshire months ago in a video that went around as well. It 'happened' because people online appreciate Senator Lee, who shared the clip, and the senator's message on spending and our broken congress."

It was appreciated, but hardly ideal. Campaigns are prohibited from using floor speeches for expressly political purposes. Paul's previous "filibusters" benefited from free media, as his campaign -- which could alert donors to what was happening -- could not exploit them the way it could exploit a town hall or debate moment. Paul's campaign could not say how much money had been raised since the video went viral.