How Negative Advertising Works (And When it Doesn't)

Harvard Business Online's John Quelch: "Greater Good: How Good Marketing Makes For Better Democracy by John Quelch and Katherine Jocz (Harvard Business Press 2008)."

"Fear appeal" ads, such as the 3am phone call, designed to worry voters about Obama’s lack of experience.

Guilt-by-association ads that include footage of Pastor Wright.

The roll-your-own ads that exploit gaffes or contradictions using the candidate’s own words.

Finally, there is the occasional policy comparison ad