Anyone who thinks that posting anonymous comments on an Internet bulletin board is a harmless diversion should pay close attention to what happens to John Mackey.

Mackey, Whole Foods CEO, was outed this week as "Rahodeb," a frequent visitor to Yahoo chat rooms dedicated to stock trading. In his comments, Rahodeb was unstintingly bullish on the prospects of Whole Foods' continuing growth, and frequently critical of a rival company, Wild Oats.

It's not clear whether he violated any securities laws in his pseudonymous postings, but his comments could end up hurting Whole Foods shareholders in another way. The Federal Trade Commission is using some of his remarks to bolster its contention that Whole Foods' planned acquisition of Wild Oats, announced in February, would be anti-competitive.

In a court filing Tuesday, the FTC referred to Mackey's postings to back up its position.

Corporate governance experts and image consultants say that Mackey's exposure as an anonymous commentator could cause the company's board to question his leadership abilities.

"This evidence raises more doubts about his sanity than his criminality," says Jack Coffee, a securities law expert at Columbia Law School. "The merger is a major business strategy, and he's undercut it with reckless, self-destructive behavior. It's a little weird, like catching him as a peeping Tom."

Wednesday, after The Wall Street Journal identified Mackey as Rahodeb, Whole Foods acknowledged that the CEO had posted anonymous comments from 1999 through 2006 using the handle, an anagram of his wife's name, Deborah.

Yahoo on Thursday put up a link from its Finance page to all 1,394 postings with Mackey's screen name on all its message boards, going back to 1999.

While some of Mackey's postings sound like news releases from Whole Foods, citing same-store sales and compound annual growth, others convey the sarcastic, overheated atmosphere that often pervades Internet message boards.

"If you don't like my posts, put me on 'ignore,' " Rahodeb wrote on May 6, 2005. "No one is forcing you to read my posts. If you think I'm an 'autistic dyslexic parrot' then simply stop reading my posts. Do you know how the 'ignore' feature works? Maybe you aren't as clever as you think you are?"

In other posts, Rahodeb bashes Wild Oats, noting that in all its years as a public company, Wild Oats hasn't turned a profit. In February 2005, Rahodeb gleefully noted that Wild Oats would have to restate its earnings.

"In my book this means that OATS has been misleading its investors for years now and is almost bound to result in shareholder litigation," he wrote. "It also means that OATS leadership lacks either competence or integrity and probably both."