-By Mike Shields, Mediaweek

NEW YORK In what has been an overall lackluster year to date for political advertising online, Sen. Barack Obama has outdueled Sen. John McCain at generating exposure and traffic on the Internet -- at least through the first six months of the year, according to a new study by comScore.

Obama averaged more than 90 million display ad impressions per month from January to June versus McCain's average of 7.4 million, per comScore. That disparity peaked in June -- however, it should be noted that this gap in activity occurred when Obama's campaign was in the final stages of a prolonged primary battle with Sen. Hillary Clinton, while McCain had wrapped up his party's nomination months earlier.

On the search front, where McCain has been the more active advertiser, based on various recent reports -- Obama is generating far more "natural" searches. ComScore found that from January to June Obama's name averaged 5.4 million search queries a month versus McCain's average of 1.3 million.

Thus, as a result of the heavier search interest and display ad volume, Obama's Web site has consistently drawn a larger crowd, averaging four times as many unique users from January to June (2.2 million versus 583,000).

However, one Web tactic has been employed more effectively in McCain's favor -- video. According to comScore's report, because of JohnMcCain.com's emphasis on video offerings, the site streamed over 2.1 million clips per month from January to June, versus just 612,000 for Obama's site. Of course, those figures do not take into account either candidate's YouTube channels, where Obama dominates; McCain's channel had generated close to 10 million views so far, while Obama's had generated 53 million.

Though Obama clearly has been more active than McCain on the Web, neither campaign is said to be spending a large portion of its vast media budget for the 2008 presidential race. Some predict such spending will escalate following the recent selections of both candidates' running mates and the conclusion of both parties' conventions. If this year's activity provides any indication of where things are headed, each candidate is likely to employ a distinct set of tactics as the process goes forward, according to comScore analyst Andrew Lipsman.

"While Obama's ads tend to be brand-building ads encouraging people to join the movement, McCain's ads are often issue-oriented," he said. "Additionally, while Obama ads have an almost universally positive message, McCain ads feature a mix of positive and negative messages."