With Wal-Mart Stores, Inc. 's (NYSE:WMT) head of advertising gone along with another marketing exec from the world's largest retailer, the company -- as widely expected -- has booted its brand-new ad agency, just a few months before work was to begin in its effort to revitalize the image and sales of the world's largest retailer.

The ad agency, which is Chicago-based DraftFCB and a division of the Interpublic Group of Companies, Inc. (NYSE:IPG) -- won a very nice $570 million deal with the ad account of Wal-Mart just this year -- but it's gone now. The world's largest retailer dropped DraftFCB just two days after the exit of Julie Roehm, who was Wal-Mart's head of advertising.

Why did Wal-Mart just completely shake up it entire ad department and ad agency so suddenly? The company's decision to take the account back from DraftFCB "is the result of new information we have obtained over the past few weeks," according to the company. Hmm -- I wonder what that super-secret information was? Julie Roehm has been accused of accepting gifts from ad agencies and having an improper relationship with a subordinate. In addition, when Wal-Mart selects a new agency, DraftFCB won't be eligible to compete for the account.