Amazon's Kindle Fire is not selling as well as expected, says Pacific Crest analyst Chad Bartley.

Bartley is cutting his estimate for the holiday quarter to 6 million units, down from 8 million, according to Tiernan Ray at Barron's who has the note.

For next year, he's projecting sales of just 10.5 million units, down from his previous estimate of 12.5 million.

For some context, Citi is calling for 23 million iPads sold this quarter, and 83 million iPads sold for fiscal 2013.

Why is Bartley calling for such a low 2013 prediction? He tells Ray over email that demand for the Kindle Fire is very weak and "the Fire seems to be a highly seasonal item."

This is something we observed last year. After taking a lot of share during the holiday quarter, it lost share in the first quarter of the year.

We called the Kindle Fire the "fruitcake of tablets." A lot of people bought Kindle Fires during the holidays because they were relatively inexpensive, but nice-seeming presents. But when it was time to buy a tablet for themselves, they didn't buy a Fire because it's not actually all that good.

Bartley says weak demand implies that Amazon is struggling to compete with Apple and to a lesser extent, Google.

In the short run, this is actually good for Amazon. It means it's selling fewer money-losing tablets, which helps its bottom line.

In the long run, it's bad. Amazon's entire tablet bet is predicated on the idea that the more people buy Amazon tablets, the more digital purchases they make from Amazon over time. If no one is buying tablets, then fewer people are going to buy Amazon's digital goods.

It's also bad news for Amazon's reported plan to release a smartphone.

If it can't crack Apple's grip on the tablet market, then what chance does it have to beat Apple, Android, and Microsoft in smartphones?

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