There are a few sure signs that the holiday season is upon us:

  • Christmas inflatables are popping up on suburban front lawns.
  • The Cincinnati Bengals are mathematically eliminated from the NFL playoffs.
  • Amazon.com's (NASDAQ:AMZN) Kindle is out of stock.

Just as Amazon ran out of its proprietary e-book readers shortly after last November's debut, the leading online retailer is once again sold out.

"Usually ships within 11-13 weeks," reads the website's product page.

Usually? That is some awkward language for a company that prides itself on snappy deliveries.

Supply, not demand, kept the trendy gadgets out of consumers' hands last year. This time, demand doesn't appear to be a problem, after the gadget scored some serious Oprah Winfrey gushing last month.

In fact, Amazon isn't even prominently pitching its reader on its landing page anymore, the way it did through last season's outage. CEO Jeff Bezos doesn't want to play Grinch two years in a row.

So what's going on here? How stupid must Amazon be to create a great marketing push with Winfrey less than a month ago, for a product that it won't be able to market during the year's biggest selling season?

Well, the answer is fairly obvious if you connect the dots. TechCrunch is citing sources that claim that the next generation of Kindle readers will be out early in the first quarter. Psst. That's roughly "within 11-13 weeks," for those marking their calendars at home.

In that light, the delay makes sense. Just as Apple (NASDAQ:AAPL) slows down retailer shipments before a new product refresh, Amazon is also gearing up for new and improved Kindle readers.

The company's timing is terrible, of course. It should have hit the market with these puppies in October, when Bezos was on Winfrey's show. Instead, it lets rival Sony's (NYSE:SNE) Reader, and smaller niche players, carve up market share over the holidays. Amazon got the market pumped about e-books last month, and now it's the one company that isn't delivering the goods. Ouch.

Amazon's temporary absence from the $359 gizmo market also opens the door to even more netbooks. With the big PC makers like Hewlett-Packard (NYSE:HPQ) and Dell (NASDAQ:DELL) diving into the mini-sized laptop arena, does Amazon really want even more devices that can -- in a pinch -- double as imperfect yet somewhat capable e-book readers?

Amazon is usually so good during the holidays. We expect fumbles from the Bengals, but it's a surprise to see Amazon bungle its most important product.

Other page-turners in the Kindle saga: