Instructive New York Times piece about how corporate PR is finding its way — unacknowledged — into Blogs.

Brian Pickrell, a blogger, recently posted a note on his Web site attacking state legislation that would force Wal-Mart Stores to spend more on employee health insurance. “All across the country, newspaper editorial boards — no great friends of business — are ripping the bills,” he wrote.

It was the kind of pro-Wal-Mart comment the giant retailer might write itself. And, in fact, it did.

Several sentences in Mr. Pickrell’s Jan. 20 posting — and others from different days — are identical to those written by an employee at one of Wal-Mart’s public relations firms and distributed by e-mail to bloggers.

Under assault as never before, Wal-Mart is increasingly looking beyond the mainstream media and working directly with bloggers, feeding them exclusive nuggets of news, suggesting topics for postings and even inviting them to visit its corporate headquarters.

But the strategy raises questions about what bloggers, who pride themselves on independence, should disclose to readers. Wal-Mart, the nation’s largest private employer, has been forthright with bloggers about the origins of its communications, and the company and its public relations firm, Edelman, say they do not compensate the bloggers.

But some bloggers have posted information from Wal-Mart, at times word for word, without revealing where it came from.

Glenn Reynolds, the founder of Instapundit.com, one of the oldest blogs on the Web, said that even in the blogosphere, which is renowned for its lack of rules, a basic tenet applies: “If I reprint something, I say where it came from. A blog is about your voice, it seems to me, not somebody else’s.”

Quite. Caveat lector.