This is used when there is some bad news, some negative propaganda against your cause. So there is TRUE information, already in the public domain, which cannot be debunked or discredited, which is negative against your cause. The strategy here is to create a fog of information, by throwing some demonstrably FALSE information, ALSO negative against your cause, into the mix. Then, when the false information is debunked (either you or a stooge 3d party can do this), its association with the TRUE information has a generally discrediting effect on ALL information or propaganda against your cause, especially with those who follow the news or information only casually. At the very minimum, confusion is sown. The casual reader will say, "It's all so confusing. I don't know what to believe anymore."
The example RW "cause" I will use here will be, of course, the Bush Administration Invasion/Occupation of Iraq.
Example 1: Controversy over flag draped coffin photos. Publication of photos of coffins of war dead tends to have a negative propaganda effect against the cause. In response to FOIA request for photos, photos of NASA astronaut coffins are also included, whether on purpose or by mistake, and are published along with the "real" war dead coffin photos. News stories appear focusing on the NASA astronaut photos being mistakenly released and published. RW echo chamber shows and websites trumpet these stories. Of course, none of this actually changes the fact of Americans and Iraqis dying in the war, but the focus is now on a nonstory about astronaut photos. Furthermore, the propaganda value of the photos is diminished because there is some general doubt and confusion sown about whether any of the photos are actually of war dead, even though most are.
Example 2: Abu Ghraib prison abuse/torture photos. Release of these photos is a huge negative propaganda event against "the cause" both internationally, and, most importantly, at home. Some websites appear which show not only the "real" released prison photos, but also have mixed in (whether by mistake or on purpose) photos from porn sites that appear to depict rape by U.S. soldiers but are actually just manufactured porn. (Note that there are apparently ACTUAL authentic photos depicting rape at Abu Ghraib prison, as yet unreleased.) The "fake rape" photos are widely disseminated and discussed. The inevitable news articles appear noting the existence of these photos and debunking their authenticity. In fact, a "reporter" even brings this up during a WH press gaggle on Abu Ghraib, adding a veil of legitimacy to this "noise". (Search for "Worldnet" in the page below and you'll find the "plant" reporter question).
http://www.whitehouse.gov/news/releases/2004/05/20040510-14.html The allegedly faked British abuse photos also falls under the category of noise/signal. The net effect is that the casual observer may well conclude that ALL the photos were some kind of hoax and not be aware of the reality of some. Furthermore, the casual observer/media customer may be innoculated against the eventual release of REAL photos of rape by US servicement. "Wasn't it shown that all those rape photos were fake and copped from some porno site?"
More on this later when I've had some time to sleep.