Barnes & Noble Inc. (BKS), which primarily competes with Amazon.com, Inc. (AMZN), could face additional pressure from a new activist investor coming onto the scene.

Barnes & Noble Inc. (BKS), one of the largest booksellers in the United States, faces a number of competitive threats from a migration to the Internet for reading as well as larger online retailers like Amazon.com (AMZN). As a result, at least one activist investor is challenging the company to make key changes to enhance its business for the new century.

Since late last year, Ron Burkle has been aggressively buying up shares of the bookseller, which even led the company to adopting a poison pill to protect it from takeover. The activists latest move to double his stake to 37% of the troubled company would make him the largest shareholder, ahead of company insiders that own just over 30%.

In recent letters contained within 13D filings, Mr. Burkle characterized the company’s stock as undervalued and criticized the company for not letting him increase his stake without triggering anti-takeover provisions. Meanwhile, the company insists that it remains in a good positive, given the circumstances, and it has already made efforts to change.

While the activist investor hasn’t articulated his strategy to turn around the book seller, many investors are looking forward to the involvement brining some real change to a struggling company.

Take-Two Interactive (TTWO) may have more than its restructuring to deal with as billionaire activist investor Carl Icahn continues to amass a stake in the troubled gaming company. Mr. Icahn added more than 300,000 shares to his position throughout February and now owns nearly 11 million shares through his various investment vehicles.

“I’m a firm believer in the long-term potential of the company, and from a corporate governance point of view I applaud the current board for its responsiveness,” said Mr. Icahn in January when he was seeking board seats. However, the activist has yet to directly come out and detail its plans for the company, although some analysts expect him to push for a sale.

Carl Icahn is also actively pushing for changes in Lions Gate Entertainment (LGF) where he made a hostile bid to increase his stake in the firm. In an interview, the activist expressed concerns that the company would pay too much for acquiring a library like MGM or Miramax, especially in light of the decline in value of libraries as a whole.

Whether either of these bids prove to be successful in unlocking shareholder value remains to be seen, but many investors remain bullish on the activist’s success in the past.

Gabelli Global Multimedia Trust Inc. (NYSE: GGT), a closed-end management investment company, is facing pressure from Western Investment LLC after it nominated two directors to the firm’s board in a Schedule 13D filing with the U.S. Securities and Exchange Commission.

To this end, Western Investments submitted Arthur D. Lipson and Gregory R. Dube for consideration at the company’s upcoming 2010 annual meeting of stockholders. Meanwhile, the firm also petitioned for the declassification of the company’s board elections.

Currently, Western Investment owns approximately 711,518 shares, which it acquired at an aggregate purchase price of $4,228,912. The company acquired the shares based on their belief that the stock was significantly undervalued and an attractive investment opportunity.