billboard liberation
n. A modification of a billboard or other advertisement that changes or subverts the ad‘s message.

Example Citations:
Filling cars with cement? Maybe, but that could alienate the general public. Chaining themselves to various buildings? Definitely, but they first must figure out which “lock-down” technique to use. An aerial assault, possibly some parachutes? Get real. billboard liberation? Oh, yes.
—Helene Cooper, “Washington boot camp offers crash training for free-trade foes,” Wall Street Journal, September 26, 1999

But these particular young rabble-rousers were also anarchists, nineties-style, congregating to parse strategies of “culture jamming,” “billboard liberation,” artistic media manipulation and alternative economics.
—Hal Niedzviecki, “Manufacturing dissent: Revolution, now?,” The Globe and Mail (Canada), August 22, 1998

Earliest Citation:
Billboard liberation amounts to property destruction and I personally can‘t advocate that kind of behavior. But I must confess I do get a chuckle when I see a bus shelter ad featuring a too-thin underwear model turned into a ghastly skeleton with no more than a few simple strokes of a black magic marker.
—Karl Mamer, “Culture Jammers Expose Advertisers, Marketers,“ The Toronto Sun, April 12, 1998

Related Words: