Priorities, headed by former White House deputy press secretary Bill Burton, had a fraction of Rove, Romney or Obama’s funding. Still, by Election Day, its anti-Romney videos were among some of the most effective and memorable of the cycle — even though several lived only online or came to TV as paid advertisements weeks and months after their digital debuts.

Burton’s ads drew an average of 288,000 views each on YouTube, six times the average enjoyed by the clips posted by Rove’s twin super PACs Crossroads GPS and American Crossroads. However, Burton’s group paid for those views in pre-roll advertising buys from YouTube while the Crossroad’s efforts on YouTube were viral and free. What’s more, Burton’s outfit garnered three times as many views on average per video as the official Romney campaign…

Burton shares the assessment of his rivals. “They made huge mistakes on how they spent their money,” he said. “They had a huge organization that had a tremendous amount of money and they squandered most of it.”…

Another important advantage to going big online came from Democratic pollster Jef Pollock, who told Burton that younger voters were a huge untapped block of independent, persuadable voters because most were less informed than their elders. That group, ages 18 to 44, largely zipped through TV commercials — if they watched shows on their television sets at all.