Barnes & Noble Inc. (BKS) announced Tuesday that it had adopted a so-called shareholder rights plan to ward off "efforts to obtain control of the Company that are inconsistent with the best interests of the Company and its stockholders."

The company didn't go into specifics, but it is likely a response to billionaire Ronald Burkle's recent disclosure that he had boosted his stake in the company to 17.8%. In a press release, Barnes & Noble disclosed how the rights work:

Ronald W. Burkle, the grocery magnate with a net worth estimated at more than $3 billion, has acquired an 8.3% stake in Barnes & Noble (NYSE: BKS) through his Yucaipa American Funds, LLC investment vehicle.

The 13-D contained nothing especially interesting -- just the usual boilerplate: The shares were acquired for investment purposes, but also reserved the right to talk to other investors or management about ways to maximize value. The 13-D added that the shares were acquired because the investors believed they "were undervalued by the market at the time they were acquired."

The Wall Street Journal notes (subscription required) that while the company has seen its performance battered by economic woes, it has a strong balance sheet and competent management. If Borders Group (NYSE: BGP) collapses, Barnes & Noble could be the most direct beneficiary. The deathwatch is one, with shares of Borders trading around 50 cents per pop.

Given the high regard that the company's management is held in, this investment seems unlikely to turn into a true activist situation: So while Burkle's investment is a strong vote of confidence from a highly respected mogul, it's not likely to be much of a catalyst for anything.

Ronald Burkle was recently the subject of a big profile in Forbes.com. The publication does like to write-up billionaires. Besides, Burkle has big-time friends, such as former President Bill Clinton, and he's a big believer in the investment principles of Warren Buffett.

Burkle built his fortune by using leverage buyouts, starting in the grocery sector. One of his most famous plays was for Pathmark Stores (NASDAQ:PTMK).

Now it looks like he wants to start a "corporate governance fund." That's a nice sounding name for a more aggressive approach to investing – that is, taking sizeable positions in a stock and agitating for change (i.e., profits). He says he was inspired by the power he saw Kirk Kerkorian had with GM, despite owning only 10% of the company.

Given Burkle's track record, he should have little trouble finding backers. And there should be no shortage of under-performing companies to target.

Going into 2007, expect this corporate drama to continue.

Tom Taulli is the author of various books, including the Complete M&A Handbook and operates InvestorOffering.com.