• by Mark Walsh  @markfwal, November 3, 2008

Barack Obama's campaign stepped up online advertising in September as the financial crisis emerged as a major issue in the presidential election.

Display ad impressions via Obama's campaign grew fourfold from Sept. 15-22 and 94% during the following week, according to new data from Nielsen Online on the candidates' online advertising in the closing weeks of the campaign.

The McCain campaign's display ad effort peaked in the weeks leading up to the Republican National Convention, jumping more than fivefold from Aug. 11-18. After the convention and announcement of Sarah Palin as McCain's running mate, however, the campaign's display ad efforts dropped sharply by 85%, from Aug. 25 to Sept. 1.

The lowest level of Obama's display ad impressions over the last two months, however, was still twice that of McCain's. Obama's campaign also increased its sponsored link advertising lately, surpassing McCain's sponsored link advertising for the first time in the week beginning Oct. 13.

While monthly traffic to McCain's campaign Web site increased a healthy 56% in September, compared to 31% for Obama, the Democratic candidate's site online audience was still nearly twice as large at 7.9 million to 4.2 million.

McCain also made gains in online video--more than tripling streams and unique visitors to video material posted on his site in September to 3.2 million and 1.3 million, respectively. Obama's video streams and unique visitors increased 60% and 35%, respectively, to 2 million and 1.1 million.

More recent data from Web video-tracking company TubeMogul shows that McCain appears to be pulling back on video efforts on his YouTube channel. The number of videos released in October on YouTube was down 37% from September and the same as in August.

In October, Obama also led McCain every day in daily views on YouTube by an average difference of 514,749, according to TubeMogul.

When it comes to online buzz, Obama managed to light up the blogosphere last week in connection with his half-hour infomercial aired on CBS, NBC, Fox and Univision. Obama accounted for almost 3% of all blog posts compared to 1.5% for McCain at the end of October.