The mistake advertisers are making now

FORTUNE — Some ad-industry groups are warning against placing advertisements on pirate sites. The Association of National Advertisers and the American Association of Advertising Agencies released a “statement of best practices” on Thursday, which also has the support of the Interactive Advertising Bureau. Adweek declared the statement to be a “major step” in the fight against piracy. But it seems unlikely to do much good.

Marketers, according to the statement, should state in contracts and insertion orders that ads are not to be placed on “rogue” sites that traffic in pirated, copyrighted material such as music and video. To people who have never visited a pirate site, that might sound like a great idea — a way to  hit the pirates where it hurts: their wallets. But if you’ve ever visited Pirate Bay or other such sites, you’ll know that “best practices” aren’t at the top of the list of concerns for the outfits that advertise on them.

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On Pirate Bay, one ad simply reads “Click Here to Start Download.” This is a common tactic on file-sharing sites, which often run ads designed to hoodwink their own more-gullible (or at least, less practiced) users. In this case, the link doesn’t download the illicit movie you just searched for: it links straight to an executable file that loads software on your computer that the advertiser promises will enable downloads of YouTube videos. Even worse, another ad for the same software product, placed right next to the search results, simply says “Download This Movie.” Classy.

On isoHunt, an ad reading “Download Now” (again clearly aimed at fooling the site’s own users) links to a software product that supposedly manages downloads better than browsers do. At least that one’s sort of relevant.

At TorrentReactor, a little pop-up ad at the bottom of the page displays a photo of a comely lass who goes by “just4play1968.” It says: “Hey you, wanna hang out? Let’s meet up in Oakland.” I live in Oakland, but I assume that just4play1968 says “Let’s meet up in Orlando” to illicit-download seekers who live there.  The ad is for AdultFriendFinders, a site for swingers — and not the Benny Goodman or even the Jon Favreau kind.

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On that same site, a search for Star Wars yields an ad placed in the middle of the search results. It reads: “Warning: Are you going to download Star Wars?” But this isn’t an admonishment that what you’re about to do is illegal or wrong. Downloading an illicit copy of Star Wars “can be dangerous and cause a copyright infringement notice,” according to the ad. The product being advertised is a “special program” that “allows you to be anonymous in bit torrent networks.”

In a statement, Bob Liodice, CEO of the Association of National Advertisers said ads can “lend inadvertent legitimacy to the illicit business models and can mislead consumers into believing that these ‘rogue’ websites are offering authentic products and complying with the law.” That might be true if the ads were from of Proctor & Gamble (PG) or Toyota (TM). But the ads that tend to appear on such sites don’t seem likely to lend legitimacy to anything. Neither Liodice nor the American Association of Advertising Agencies responded to a request for comment Friday morning.

Instituting “best practices” can’t hurt, except insofar as it creates the false idea that the marketplace can by itself deter piracy. But it’s unlikely to stanch the flow of revenues to sites that employ the worst practices.

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