Best Buy CEO Brian Dunn is never at a loss for words.

Whether speaking to Wall Street analysts or at industry conferences, Dunn cheerfully and unapologetically stumps for the Richfield-based consumer electronics giant, often using words like "powerful" and "explosive" to describe the company's prospects.

But a recent blog post from Dunn took on a different hue: that of a CEO and company under fire.

Writing on The D. Brief, his occasional blog, Dunn lashed out at critics, specifically unnamed members of the news media.

"There are those who question the validity of Best Buy's business model," Dunn wrote. "This misguided perspective is especially troubling for me, because it blatantly and recklessly ignores overwhelming evidence to the contrary."

"We fully expect to receive our share of criticism -- we're a big company and we don't always get everything right," he later added. "But this is one of those times when I felt it was necessary not only to acknowledge our shortcomings, but to set the record straight on issues where facts are being obscured by rhetoric."

A major Fortune 500 using social media to respond to critics carries its own rewards and risks, communication experts say.

"Bad news in the mainstream is chewed over in social channels, and vice versa; increasingly, corporate leaders will feel compelled to respond," Todd Defren, principal at social media and public relations firm Shift Communications in Boston, wrote in an e-mail. "Dunn's response was appropriate but likely struck a defensive chord to outside observers."

Richard Levick, CEO of Levick Strategic Communications in Washington, D.C., applauds Dunn for communicating directly to the public, noting that Southwest Airlines and Marriott CEOs do the same thing.

And Best Buy spokeswoman Susan Busch said social media is how Dunn engages with consumers.

"It provides us with a great tool for listening to our customers, employees and communities. It's important and necessary that we are out there," she added.

Dunn was attending the Consumer Electronics Show in Las Vegas and was not available for comment.

Communication experts say it's not uncommon for CEOs to stand up for their companies through social media, but they say Dunn's tone was overly defensive.

In the first half of the blog, Dunn apologizes for Best Buy's inability to process online orders in time for Christmas. "We know we did not deliver a good experience and we're truly sorry," Dunn said.

But the message soon soured as he addressed criticism for the company's missteps.

"It's like apologizing to your wife for forgetting your anniversary and then reminding her that you remembered to pay the mortgage," Levick said.

It's no secret that Dunn has his critics. Since he ascended to the job in June 2009, Best Buy's stock price has declined more than 40 percent. Until recently, Best Buy hadn't generated a same-store sales increase since the first quarter of 2011.

Whispers abound about the fate of Dunn's job.

Up until now, Dunn, at least publicly, has remained above the fray. But then 2012 began.

On Jan. 4, Forbes tech columnist Larry Downes wrote a scathing piece on Best Buy titled, "Why Best Buy is going out of business -- gradually."

"Electronics retailer Best Buy is headed for the exits," Downes said. "I can't say when exactly, but my guess is that it's only a matter of time, maybe a few more years."

Two days later, the same day Dunn wrote on his blog, the company reported holiday sales at stores open for at least a year in December fell a disappointing 1.2 percent.

In fairness, Dunn faces enormous challenges, especially figuring how Best Buy stores will coexist with e-commerce.

"All of the real estate a big box has definitely raises the question: How big is too big?" said Alison Paul, vice chairman and U.S. retail and distribution leader for consulting firm Deloitte.

In his post, Dunn defended the vitality of bricks and mortar, citing a recent study by the NPD Group Inc. that said 80 percent of consumer electronics revenue still moves through the physical store.

But Levick thinks Dunn is a bit out of a touch.

"He is still using the language of the past," Levick said. "There's no vision there."

Thomas Lee • 612-673-4113