The analysis shows that the campaign voicemail gaffe helped to push Brown’s name past Republican Meg Whitman’s in both national online buzz  and in on-air television mentions in California’s top media markets. It had been at least 10 days since Brown led his opponent in either category, but the negative exposure was certainly not the way the campaign would have liked to take the lead.

The drama occurred during a week where both campaigns significantly stepped up their overall ad buys. Whitman aired  3,727 ads across California’s top four media markets last week, 51 percent more than her total during the previous week. Brown, meanwhile, aired 2,804 ads in the same markets, a 60 percent increase over the previous week.

In other campaigns across the nation:

• While Republican Carly Fiorina made a serious move in the advertising battle last week, Democratic incumbent Barbara Boxer still ran more ads overall. Boxer continues to receive good news in polling results for the California Senate race, driving positive online buzz.
• Alex Sink’s gubernatorial campaign in Florida ran only five total ads in Jacksonville and was silent in Miami, Orlando, Tampa, and West Palm Beach. Rick Scott, meanwhile, blanketed the airwaves with almost 1,400 total ads. But ads bought and aired by the Florida Democratic Party helped to balance out Scott’s message on the airwaves.
• While the latest public polls appear to be in Democratic Governor Martin O’Malley’s favor, Republican Bob Ehrlich accelerated his advertising buy last week as the campaign enters its final month.
• In Pennsylvania’s U.S. Senate race, Republican Pat Toomey increased his advertising lead last week over Democrat Joe Sestak. Support from the Democratic Senatorial Campaign Committee is driving negative discussion about Toomey on-air, and help from the White House is propelling Sestak’s climb in online buzz.

Download Nielsen’s Campaign Media Analysis for more details on these and other contentious midterm political races.

Meanwhile in the race for Crist’s gubernatorial seat, Republican Rick Scott aired four times as many ads last week as his opponent Alex Sink (D). Both candidates aired their highest number of ads in the Tampa-St. Petersburg market, but the most obvious discrepancy came in the Miami market, where Scott’s campaign aired 344 ads as Sink’s campaign aired none.

In other high-profile races across the country:

• Meg Whitman led gubernatorial opponent Jerry Brown in overall advertising across the top four California media markets. But news that the former eBay CEO once employed an undocumented worker at her home drew a spike in online buzz and overall TV mentions on September 30.
• Carly Fiorina enjoyed her first full week advertising during the general election for California’s Senate seat. While Fiorina’s ads aired in Los Angeles, Sacramento, and San Diego, she still had yet to air an ad in the San Francisco market, through October 3. Overall, Democratic incumbent Barbara Boxer held a nearly 4-to-1 advertising advantage across the state last week.
• The Baltimore market is proving to be the biggest battleground in the Maryland governor’s race. Incumbent Martin O’Malley (D) and opponent Bob Ehrlich (R) were neck-and-neck in Charm City’s ad race, while Ehrlich showed no advertising activity at all in the Washington, DC market. As a result, the candidates’ names were more than twice as likely to be mentioned on local Baltimore television stations last week, compared to the DC airwaves.

Download Nielsen’s Campaign Media Analysis on these and other contentious mid-term political races.

VIRGINIA: The ad race between Virginia gubernatorial candidates continues to be as tight as it was reported two weeks ago. Since September 21st Robert McDonnell(R) has out-placed Creigh Deeds (D) 6215 to 5718.

A breakdown of the Designated Market Areas (DMAs) within Virginia lends a better view of where the candidates are targeting their messages. McDonnell is dominating the airwaves in the Richmond and Norfolk markets, where his campaign has placed about 40% more ads than Deeds’s campaign since September 21st.  But Deeds, the Democratic candidate, is more of a presence on TVs in the rural Western part of the state, where he’s bought 16% more ads than the McDonnell campaign in the Roanoke-Lynchburg market and 19% more in the Tri-Cities market in the last month. In the Washington DC market, the two candidates are virtually tied, with each of the campaigns placing roughly 1700 ads from 9/21 to 10/19.

NEW JERSEY: In Nielsen’s last analysis of the governor’s race two weeks ago, incumbent Democrat John Corzine showed a big lead in ad buys over Republican challenger Chris Christie. And that lead hasn’t waivered, with Corzine’s campaign placing almost 2 1/2 times as many ads on New Jersey TVs as Christie’s, since September 21st through October 19th (4131 to 1786).

But ads placed by the campaigns alone do not tell the entire story in New Jersey.  The Republican Governors’ Association has chipped in with its own advertising on behalf of Christie. The RGA placed over 900 ads over the last month to help close the gap.

NEW YORK CITY: Incumbent Mike Bloomberg continues to dominate New York airwaves over his opponent Bill Thompson (D). Bloomberg’s 2,875 TV ads placed since September 21st, almost 1,300 more than the amount placed by Thompson over the same period.

NEW YORK CITY: Incumbent Mayor Mike Bloomberg is dominating his competition in the ad buying race. Between June 1^st and September 20^th, Bloomberg purchased 4,706 TV ads in the New York market – no small feat considering New York is one of the most expensive markets in the country. The figure dwarfs the number of ads bought by Democratic challenger Bill Thompson, whose campaign bought just 14 TV ads over the same period – all of which ran on or after September 18^th.

NEW JERSEY: Recent polls show a slim lead for former prosecutor Chris Christie over incumbent Governor John Corzine. But since Christie was tapped as the Republican nominee back in June, the ad race has been much more lopsided in favor of his Democratic rival. Gov. Corzine has placed 3 ½ times more TV ads from June 3^rd to September 20^th, outscoring Christie 4,806 to 1,393 in the New York City and Philadelphia markets combined.

VIRGINIA: In the Old Dominion governor’s race, Republican Robert McDonnell hopes that history repeats itself as he takes on a Democratic opponent in Creigh Deeds whom he narrowly beat out for the attorney general seat four years ago. Since the Virginia primary ended in June, McDonnell has placed more ads across Virginia’s multiple TV markets with a score of 4,382 to 3,986 through September 20^th. But more recently, Deeds has been a bigger presence on Virginans’ TV sets with 3,028 ads in the first three weeks of September alone compared to 2,753 ad buys for McDonnell.

Just weeks after his inauguration in 1993 President Bill Clinton also held a prime time news conference. That event focused on the economy and was carried by 4 networks on February 15, 1993. The sum of the audience of those networks was a 42.1 household rating with 64,300,000 viewers on average.

On October 11, 2001, exactly a month after the attacks of September 11, President Bush held a prime time news conference that was carried by 7 networks. The sum of those networks’ audience from approximately 8-8:45PM was a 42.0 household rating with 64,813,000 viewers.

In 1993 the average U.S. TV home had approximately 40 channels available. By 2000 the average home had 61 channels and now that figure has increased to more than 118 channels available.

Web traffic to sites within the “Current Events and Global News” category was up 27% on Election Day, versus the previous Tuesday (Oct. 28), Nielsen Online reported Wednesday.

The candidates’ websites also drew healthy traffic on Election Day.  Obama’s site had 1.2 million unique visitors on Nov. 4, while McCain’s site had 479,000 unique visitors.

Page views and time-per-person at current events and news websites also increased 103% and 61%, respectively, on Tuesday, according to Nielsen.

Check out historical unique audience data from Election Day 2004.

View the full media alert.

Read coverage of Nielsen’s findings in Ad Age, Silicon Alley Insider, Mediaweek, Media Life magazine, and Direct News.

Live news coverage was carried on both broadcast and cable networks, including Spanish-language networks: ABC, CBS, FOX Broadcast, NBC, Telemundo, Univision, BBC America, BET, CNBC, CNN, FOX News Channel, MSNBC, and TV One.

Nielsen’s audience estimates include primetime coverage, from 8pm to 11pm, in the Eastern and Central Time Zones and live in Mountain and Pacific Time Zones.

Audience estimates for the 8pm to 12:30am time frame, which featured Sen. McCain’s concession speech and President-Elect Obama’s speech in Chicago, are also included below.

In 2004, almost 59.2 million viewers tuned in between 8pm and 11pm to watch Election Night TV coverage, as President Bush defeated Sen. John Kerry to win re-election.

On Election Night in 2000, almost 61.6 million viewers (excluding viewers of Spanish language networks) watched primetime TV coverage of President Bush and Former Vice President Al Gore’s embattled election contest.

Nielsen’s broadcast audience numbers include a combination of national and local news coverage.

View the full media alert.

Read coverage of Nielsen’s findings by the Associated Press and Reuters, as well as in The Wall Street Journal, the Los Angeles Times, The Boston Globe, Mediaweek, and Media Life magazine.

NBC’s 8pm to 11:30pm coverage of the voting results claimed second place, and ABC’s 8pm to 9pm Election Night coverage rounded out the top three.

Election returns coverage on CBS, FOX, and Univision dominated the rest of the top ten.

Overall, ABC won the night with an average audience of just over 13.2 million viewers, while NBC took second place with almost 12.5 million average viewers. CBS and FOX claimed third and fourth places with roughly 7.4 million and 4.7 million average viewers, respectively. Univision and the CW followed in fifth and sixth places with average audiences of roughly 4 million and 2.4 million average viewers, respectively.

In the wake of winning the 2008 U.S. presidential election, Obama was mentioned in almost 20% of all blog discussions, Nielsen Online reported Wednesday.

In comparison, John McCain was referenced by just 6.3% of all blog entries posted on November 5, according to Nielsen.