For retailers, the day after the U.S. holiday of Thanksgiving on the fourth Thursday in November is a painstakingly orchestrated affair.

Prices are scientifically slashed down to the penny. Sales begin at dawn. And glossy circulars containing the well-laid plans are distributed just a day or two ahead to keep consumers and competitors in the dark.

Or at least that is how it worked before people like Michael Brim came along. Using a computer in his dorm room in California, Brim, an 18-year-old college freshman who says he rarely shops, is abruptly pulling back the curtain on the biggest shopping day of the year.

His Web site, BF2005.com, publishes the circulars for what retailers call Black Friday – the day that officially starts the holiday shopping season – weeks ahead of time. So far this year, sources have leaked advertisements to him from Toys “R” Us, Kmart and Sears.

Brim says his motive is to educate consumers. But retailers are furious, arguing that the site jeopardizes their holiday business, and they have threatened legal action. But BF2005.com is not their only problem. There are now at least three Web sites dedicated to digging up Black Friday sales secrets, creating a fierce competition to post the ads first. It is so heated, in fact, that all three sites stamp the circulars with bright electronic watermarks to discourage rivals from stealing a scoop.

Brim says he does not know the full identities of the leakers. Judging by the quality of the copies, which generally arrive as digital images or scanned copies, he suspects they are either from store employees or printing plant workers, neither of whom, he conceded, may be authorized to distribute the circulars.

Those who want to leak an advertisement have plenty of options. Besides Brim, Brad Olson, 26, administers Gottadeal.com from his parents’ house near Milwaukee, and Alan Smolek, 21, runs blackfridayads.com out of his apartment near Chicago.

Maybe I can decide, this week, whether or not to sleep in — the day after Thanksgiving.