Research group IDC (News - Alert) is increasing the forecast of sales of tablets. The group now expects tablet makers to sell 106 million of the devices this year, up from 88 million they originally forecast.

IDC said brisk sales for tablets, especially Amazon’s relatively cheap Kindle Fire, late last year prompted the increase of their forecast.

“Amazon's widely-reported entry into the media tablet market with a $199, 7-inch product seemed to raise consumers' awareness of the category worldwide despite the fact that the Fire shipped almost exclusively in the U.S. in the fourth quarter,” Tom Mainelli, a research director for Mobile Connected Devices, said. “As a result, products across the pricing spectrum sold well, including everything from Apple's (News - Alert) premium-priced iPads (which start at $499) to Pandigital's line of Android-based, entry-level tablets (which start at $120).”

Mainelli said that Apple’s success in the fourth quarter was particularly notable, since Apple, currently the market leader with their iPad, experienced an increase of 110 percent over the fourth quarter of 2010.

While Apple continues to dominate the tablet market, Android (News - Alert)-based tablets made significant gains in 2011, driven in part by Amazon’s offering. The market share of Android-based tablets grew from 32.3 percent in the third quarter of 2011 to 44.6 percent in the fourth quarter. Consequently, Apple’s market share slipped from 61.6 percent to 54.7 percent. IDC said in a press release that it expects Android to keep growing at the expense of Apple’s iOS.

“As the sole vendor shipping iOS products, Apple will remain dominant in terms of worldwide vendor unit shipments,” Mainelli said. “However, the sheer number of vendors shipping low-priced, Android-based tablets means that Google's (News - Alert) OS will overtake Apple's in terms of worldwide market share by 2015. We expect iOS to remain the revenue market share leader through the end of our 2016 forecast period and beyond.”

The other major tablet platforms suffered even worse performance. Blackberry went from 1.1. percent to 0.7 percent, while WebOS went from 5 percent all the way to zero.

Thanks to low prices, the market share of e-Paper-based e-readers has grown, from 6.5 million units in the third quarter of 2011 to 10.7 in the fourth quarter, an increase of around 65 percent. IDC expects the growth of these readers to continue into 2012. 

"Publishers in markets outside of North America are only just beginning to warm up to the idea of eBooks,” Mainelli said. “Once Amazon and others persuade these content owners to embrace digital formats, we expect eBook reader shipments into these regions to increase more rapidly.”

Other are also sanguine about tablet growth. Research and Markets expects tablet makers to ship 248.6 million units in 2012.

Apple CEO Tim Cook said in February that tablets would eventually replace PCs.