Wal-Mart shares fell three percent after a disappointing Thanksgiving weekend . Could it be that others beat WM at its own game? Britt Beemer, head of America's Research Group, which surveyed 1,000 shoppers every night over the long weekend, said one reason for the slow sales at Wal-Mart could be that it had not discounted as heavily as other retailers. "This year they did not get nearly as aggressive on the early-bird specials, and it cost them," he said, adding that rivals such as JC Penney, Best Buy, Sears and Circuit City had discounted more deeply. Of course, we shouldn't get carried away, this is just one weekend. Still, it's a good reminder that the Biggest Box is not impervious to the pressures of competition. Sears was the Wal-Mart of its day, but it faded. Now it's making a comeback bid by merging with Kmart. This is all part of the market churn where companies rise, fall and regroup.