Although Democrats are still dominating YouTube viewers' time spent on campaign-related video, Republicans are starting to gain ground, according to Nielsen/NetRatings, MarketingCharts reports.

YouTube videos about Republican presidential candidates accounted for 31 percent of the time spent at the site watching campaign-related videos in April, increasing 21 percentage points over March levels.

Videos about Democratic candidates accounted for 69 percent of all time spent on campaign videos in April, decreasing 20 percentage points since March.

"The Democrats have taken an early lead in the online race to the White House, leveraging Web 2.0 forums and technologies to their benefit," said Jason Lee, media analyst, Nielsen/NetRatings. "Of course…not all coverage is positive. In March, the anti-Hillary Clinton '1984' video drew significant traffic, which accounts in part for the Democratic lead in time spent for the month."

"By April, John McCain videos accounted for 15 percent of total time spent on candidate-related YouTube content, but that content included McCain's ill-received performance of 'Bomb Bomb Iran' and footage of the Senator snoozing during the 2007 State of the Union address," Lee added.

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