Part of the change is competitor wiliness. Part is shifting tastes of increasingly affluent American consumers away from bargain-basement big-box toward greater convenience, more selection, higher quality or better service. ("For the first time in a long time, quality has a chance to gain on price," said one industry analyst.)

And part of it, apparently, is the Internet. Wal-Mart's loss of clout "is a reflection of a more fragmented world," the Journal reports. "Big-box stores thrived by selling recognizable national brands, which themselves were fed by two phenomena: the growth of mass media and freeways, which encouraged large stores in remote areas. Stores and brands together achieved scale efficiencies that allowed them to overwhelm local chain stores and regional brands."

"But the Internet is transforming the retail definition of scale. The once-stunning compilation of 142,000 items found in a Wal-Mart supercenter doesn't seem so vast alongside the millions of products available on the Internet. At the same time, the cost of creating and sustaining a national brand is rising because of media fragmentation."

Niche brands, promoted through Internet world-of-mouth, are stealing market share. One result is that "retail giant hold less sway over their customers - and their suppliers."

A case in point: Wal-Mart brought the barcode into our lives in 1984, when it demanded that all its suppliers have them as a way to help the store check people out more efficiently. But when the retailer jumped into the next big logistics technology, radio-frequency identification, in 2003, suppliers balked. Too expensive, they said. Sorry. We used to be scared of you, but we're just not that scared anymore.