Associated Press business writer Candace Choi wrote an article earlier this week about food companies reaching out to bloggers, sometimes giving out free samples to generate buzz.  Quoting an excerpt from the article:
Obsessive Web sites evaluating the newest eats have become must-reads for lovers of every type of food including frozen dinners, potato chips, candy bars and even energy drinks. While the readerships for sites like IAteAPie and Candy Blog are only a few thousand daily, food companies court them as a way to reach an interested audience for the price of shipping a box.
Further own down, the article offers up an explanation for the tactic:

Courting one blog with a couple of thousand daily readers may not have a huge impact, but marketers can easily reach several such blogs with little effort, said Debbie Weil, a corporate blogging consultant based in Washington, D.C.

"Companies are paying attention to the concept of lots and lots of tiny little markets. Added up, it's significant," Weil said.

The single-minded focus of blogs may be in some ways more valuable than traditional marketing since it's easier to cherry-pick an audience, said Daniel Taylor, a senior analyst of digital advertising and marketing for the Yankee Group.

In essence, they're trying to grab the market by the long tail by winning the favor of influential bloggers. 

The article briefly touches on the ethical issues that the bloggers face in accepting the samples.
Like many other bloggers, Taylor usually notes when a company sends her free samples. Since the site isn't her primary source of income, Taylor doesn't think accepting samples worth a few dollars will sway her opinion.
Provided that third-party bloggers give full disclosure on what they're getting from marketers, we have a situation more transparent than the "under-the-radar" style of marketing employed by a consulting firm in the late 90s revive a flagging soft drink brand among teens, and that is definitely a good thing.

Still, I can't help but wonder whether these companies are misguided in doling out free samples to generate buzz.  Instead of coaxing others to speak for their brand, why aren't these companies letting their product development teams write about the new and improved goodies on blogs, giving a chance for real people to offer their feedback via comments?

When it comes to long-tail markets, you aren't looking for your customers so much as they are looking for what you sell, usually via organic search.  Corporate blogs not only enable a conversation with your customers, the frequently updated content stands to boost your visibility in search.