The three networks aired more than 36 minutes of commercials, including promotional announcements and public service announcements, during the DNC — compared with just 13 minutes of commercials during the GOP convention, according to Nielsen.

Of the three networks, CBS aired the most advertising during both conventions.

John McCain’s campaign ran 74% more ads during the Republican convention (11,845) than during the Democratic National Convention (6,791).  In contrast, Barack Obama’s campaign maintained consistent levels of advertising during both conventions (10,756 during the Democratic convention; 10,468 during the GOP convention).

Both parties’ committees ran more advertising during the opposing party’s convention than during their own.  The Republican National Committee Campaign ran 1,787 commercials during the Democratic Convention, but only 442 during the Republican Convention, while the Democratic National Committee Campaign aired 2,553 ads during the Republican Convention, but only 2,046 during the Democratic Convention. 

Political organizations, including “527” groups, ran approximately the same number of ads during both conventions: 22,245 spots during the Democratic convention and 25,767 during the GOP convention.

Nearly two-thirds of all U.S. households (64.5%) — 120.1 million people age two or older — watched at least one of the 2008 political conventions, according to a new analysis released Thursday by Nielsen. 

Viewership levels for the Democratic and Republican conventions were essentially even, with about half of all U.S. households watching each.  Overall, 15% of all homes tuned in to the Republican National Convention only, while 15.7% tuned in to just the Democratic National Convention.  Another 33.9% of all households tuned in to both conventions.

Homes that watched both conventions were likely to be older (age 65+) and better educated (32.3% had college degrees) than viewers who watched only one of the conventions. 

RNC-only households were usually bigger (four people or more), had higher incomes ($100,000+), and were more likely to be white, while DNC-only households were smaller (two people), less wealthy ($20,000 or less), and more likely to be African American.

One-fifth (21.2%) of DNC-only homes were headed by an African American, while 83.5% of RNC-only homes were headed someone who is white.

Similar percentages of African American and white viewers tuned in to both conventions (35.7% and 34.5%, respectively).  Among African Americans, 27.4% watched only the DNC, and only 8.1% watched only the RNC.  Meanwhile, 16.2% of white viewers watched the RNC only, and 13.6% watched the DNC only.

Read the full report — and stay tuned during the presidential debates for more Nielsen TV audience analyses.

Read coverage of Nielsen’s findings in the Baltimore Sun, The Boston Globe, Broadcasting & Cable, and Multichannel News.

Online Buzz
An analysis by Nielsen of the online discussions around more than 30 speakers at the Democratic and Republican conventions showed Obama leading McCain, followed by Palin and Sen. Hillary Clinton.  Vice-presidential candidate, Sen. Joe Biden, rounded out the top five most buzzworthy politicians.

Online Traffic
Web traffic to BarackObama.com increased 32% during the week of the Democratic National Convention.  During the same period, traffic to McCain’s website increased 242%, perhaps driven by the announcement, late in the week, of Sarah Palin as his running mate.

Still, traffic to Obama’s site outpaced traffic to McCain’s site by a two-to-one ratio in the week ending August 31.

Online Advertising
John McCain’s campaign increased its online advertising in August, with image-based impressions up by 254% month-over-month and sponsored search links up by 43%.

Barack Obama’s campaign placed fewer online ad impressions during the same time period, reducing image-based impressions by 48% and sponsored links by 18%.

View the full media alert.

Read coverage of Nielsen’s findings in TV Week, The Boston Globe, Condé Nast Portfolio, and Silicon Alley Insider.

Convention coverage from NBC and CBS also made their way into the top 10.

Overall, NBC won the night with an average audience of 6.1 million viewers, while CBS took second place with just over 5.3 million average viewers. Univision and ABC claimed third and fourth places — with just over 4.9 million and 4.6 million average viewers, respectively. FOX followed in fifth place with an average audience of slightly more than 4.4 million viewers.

The Vice Presidential message (sent in the late hours of Friday night) is, by many accounts, the single largest mobile marketing event ever in the U.S.

“From a mobile perspective, it makes sense that the campaign chose to use text-messages,” Nic Covey, Director of Insights, Nielsen Mobile, noted. “Today, 116 million U.S. mobile subscribers (52 percent of subscribers) actively use text messaging, making it a new mass medium for marketing efforts.”

Obama’s VP text-message is already being seen as one of the most important text messages ever sent, and one of the most successful brand engagements using mobile media. “The value of the message goes far beyond the 26 words and 2.9 million recipients,” Covey said. “Here, Obama branded himself as cutting edge, inflated the already enormous press attention paid to his VP pick and further established a list of supporters’ most coveted form of contact: their cell phone numbers.”

Read coverage of Nielsen’s findings in Newsday and the Los Angeles Times.

On Thursday, Nielsen joined the fray, releasing an analysis of the candidates’ online presence and buzz, their advertising campaigns, and TV viewership for past conventions. 

Online Audience and Videos Viewed
BarackObama.com’s unique audience was twice as large as JohnMcCain.com’s in both June and July 2008.  However, in July, the number of video streams on JohnMcCain.com more than doubled, possibly due to press coverage around Senator John McCain’s ad that compared Senator Barack Obama to Paris Hilton.

Blogosphere Buzz 
Senator Obama maintains the lead in overall buzz volume on blogs and message boards.  Between June 1 and August 17, Senator Obama was mentioned on blogs twice as frequently as Senator McCain.
 
Online Advertising
During the summer, the “Obama for America” image-based online advertising campaign increased fivefold — from 80 million impressions in June to 417 million impressions in July. 

TV Advertising
During June and July 2008, Senators Obama and McCain targeted their local TV spots at key battleground states including Ohio, Michigan, Pennsylvania, and Wisconsin.  Between June 4, when campaigning for the general election began, and August 1,  Senator McCain ran significantly fewer local TV spots (57,132) than Senator Obama (70,381), but placed more than twice as many national cable ads (526) as Senator Obama (142). 

TV Viewership: Past Conventions
Since 1960, only three Republican National Conventions have drawn more television households than the Democratic National Convention: 1972 (presumptive nominee Richard Nixon), 1976 (presumptive nominee Gerald Ford), and 2004 (presumptive nominee George W. Bush).

View the full press release.

Read coverage of Nielsen’s findings in The Wall Street Journal, The Boston Globe, the Los Angeles Times, the Tampa Bay Business Journal, Variety, The Hollywood Reporter, TV Week, Multichannel News, and Media Post.