The ad's reach -- it has received more than 1.7 million hits on YouTube in just a few days -- and the unmasking of its maker offer a glimpse of the changed media landscape of a nascent presidential campaign that is bitterly competitive 10 months before first voting.

The new popularity of web video allows broad distribution of clever political messages, which are often negative attack ads that may not readily be traced to their creators.

Phillip de Vellis, a strategist with the Washington-based consulting firm Blue State Digital, which hosts the Obama campaign web site, said he made the ad.

"I did it. And I'm proud of it," Mr de Vellis said in a response posted on a website site this week.

Mr de Vellis said he had acted on his own, without the knowledge of the Obama campaign or his employer.