Sales of the Kindle e-readers have apparently also fallen off a cliff

Data: IDC

FORTUNE -- Thursday was bad-news day for Amazon's (AMZN) Kindle line of tablets and e-readers.

• IDC released first quarter tablet sales data that had Kindle Fire shipments falling from 4.8 million in the Christmas quarter to less than 750,000 units last quarter. "Kindle Fire Shipments Fizzle" was the headline on AllThingsD.
• E Ink Holdings, the sole supplier of black-and-white screens for Amazon's Kindle e-readers, reported that its "major customer" bought way too many e-ink screens in Q4 2011. As a result, it ordered "almost nothing" in Q1 2012.

"To put it short," wrote Paulo Santos Thursday in Seeking Alpha, "the Kindle eReader has dropped out of bed. It has fallen beyond the wildest dreams of Amazon.com's management."

"This is simply not a positive development," Santos concludes. "This is another development confirming the migration of e-reading from Amazon.com's controlled environment, to a larger set of devices. These devices run Apple's (AAPL) iOS or Google's (GOOG) Android.

"The Kindle Fire suffering the same fate so early ... means that Amazon.com's attempt to mitigate Apple and Google's dominance has already failed. This failure certainly doesn't seem to be priced in the market."