by Scoobie Davis
Wikipedia is now correct--for the time being(It wasn't accurate yesterday)
Swiftboating is American political jargon for an ad hominem attack against a political figure, coordinated by an independent group, for the benefit of an established political force.
The name comes from the portrayal of John Kerry's decorated military experience in Vietnam by the Swift Boat Veterans For Truth organization. Its ads against Democratic presidential candidate Senator John F. Kerry in the 2004 presidential election campaign alleged that Senator Kerry was being untruthful in his representation of his military record, and was thus unfit to lead. Although the Swift Boat Veterans were ostensibly an independent group, they were a clear political windfall for Kerry's opponent, George W. Bush.
Swiftboating frequently refers to a campaign that uses viral marketing techniques to sell the exaggerations. By using credible-sounding sources to make sensational and difficult-to-disprove accusations against the opponent, the campaign leverages media tendencies to give the story far more play than it would otherwise receive. Mostly used as a pejorative, the term has gained currency among liberal writers, while its appropriateness as a description of political debate has been questioned by some conservative commentators.
Other terms used to describe political attacks
"Borking" Originated from Democratic opposition to the nomination of Robert Bork to the United States Supreme Court, 1987
"demonizing the opposition" (coined in 2003 by Paul Krugman to describe Karl Rove's methods) 
"politics of personal destruction" (frequently used during Clinton's impeachment hearings) 
ad hominem attack
Fair Game (Scientology)
Examples of the use of "swiftboating"
"Character assassination is the Karl Rove tactic of choice, eagerly mimicked by his media surrogates, whenever the White House is confronted by a critic who challenges it on matters of war. The Swift Boating is especially vicious if the critic has more battle scars than a president who connived to serve stateside and a vice president who had "other priorities" during Vietnam." –Frank Rich in the August 21, 2005 New York Times
"Swiftboating Cindy Sheehan"
"The chickenhawk attack machine (Matt Drudge, Rush Limbaugh, Bill O'Reilly, Sean Hannity, etc.) has identified Cindy Sheehan, whose son was killed in Iraq, as a threat worthy of a tarring and feathering by the swift-boat machinery... Swiftboating will not work on her"
"Swiftboating the Crazies"
"Dean is being swiftboated."
"I do think the race offered one good opportunity for out-of-state Dems and Progressives, and that was to calmly write to newspapers and try to talk to receptive radio hosts about the swiftboating of the candidate."
"I’m glad the efforts to swiftboat Paul Hackett have been exposed for what they are."
Fox News, Nov. 18, 2005 
O'Reilly Factor, Fox News Channel, Aug. 22, 2005: "The swift boating of Cindy Sheehan, that is the subject of this evening's 'Talking Points Memo'." (LexisNexis)
Swiftboat ('swift bOt); transitive verb: (1) To accuse a public figure of questionable conduct without the benefit of physical evidence, usually by an entity informally associated with a person or entity benefiting from the accusation. Noun: (2) An unsubstantiated charge made against a public figure or organization, usually made by a proxy entity. See also: Smear, hatchet job, character assassination. (3) An organization dedicated to swiftboating on behalf of a respectable organization. (4) archaic: a type of boat used by the United States Navy to patrol the shores of Vietnam from 1965 to 1970; see also PCF.