Barack Obama's new 13-minute video on John McCain's role in the "Keating Five" scandal is making waves this week, but it's only the latest salvo in what has been an ongoing ad war in cyberspace between the two candidates.
As Amy Harder discusses in a new NationalJournal.com online exclusive, Web advertising in all its incarnations is opening up a new set of opportunities -- and risks -- for presidential campaigns, and McCain and Obama are taking advantage of the technology in sharply distinctive ways.