Auto sales weren't so bad after all! we all agreed, shaking hands and congratulating the industry, feeling a bit smug (despite Toyota's walloping of all things American). And at first blush, it looked to be true: sales at Ford Motor Company (NYSE:F) were actually up vs. September 2005, 4.7%, and sales at DaimlerChrysler AG (NYSE:DCX) and General Motors Corporation (NYSE:GM) weren't down as much as many industry watchers feared.

That's all well and good, when you're looking at raw units sold. But Autoblog's John Neff went a little deeper and considered the way auto dealerships operate: in "selling days." September 2006 selling days were 26, vs. only 25 in September 2005. And if you know auto dealerships, the guys behind the desk are really looking at DSR: daily sales rate.

Were we all snookered into placidity by one of the oldest tricks in the car sales guys' book? Here's what John found when he looked at DSR instead of gross sales:

In a sign that the world's largest retailer expects to see slowing sales this fall, Wal-Mart lowered its September same-store sales forecasts. In addition to the August 1.8% same-store sale growth given just yesterday, what lies ahead?

Wal-Mart, considered to be a huge barometer of consumer spending, can cause entire market swings when it even sighs, and lowering a current-month sale-store sales forecast can send ripples throughout the national averages. We've all seen it before if we were paying attention; I know I was.

Is the American economy -- and more even, economic growth -- predicted by Wal-Mart's numbers on a monthly and even weekly basis? Many would argue yes, and there are equal opinions on the other side of this answer as well.

It's true that Wal-Mart, by virtue of its size, is a very decent indicator of the growth (or stagnation) of the American economy -- nothing new here. But, as Wal-Mart continues to grow, it may even become a larger indicator of economic spending patterns or slowdowns that could be used to actually guide some of the marketplace, which is based on speculation more than fundamentals if you ask me.