IDC sees Android's share growing by more than 50 percent from 16.3 to 24.6 in the next four years, leaving it trailing only Nokia's Symbian in activations on mobile devices. But the firm said Symbian will continue slipping, losing 18 percent of its base with a drop from 40.1 to 32.9 percent.

Fallen Apple?

There's bad news for Apple, too. It's iOS will slip 25 percent from 14.7 percent to 10.9, IDC says. But many analysts note that, considering Apple only sells versions of one device, currently only on one carrier (though that's likely to change), holding onto that kind of market share against rivals with multiple models on several carriers is impressive.

While Windows Mobile would see a 43 percent boost in IDC's projection, it would only be to a slightly less abysmal spot, up from 6.8 to 9.8 percent and still last among the top players.

IDC's research is based on interviews with vendors, proprietary advance information, distribution feeds and other data. The company said a range of new phone introductions had led to a 55 percent increase in the smartphone market over 2009. IDC senior analyst Ramon Llamas said in a statement that Android's design made it increasingly popular to carriers, application developers and users.

"Phone vendors have been drawn to Android because it allows them to present their own approach to what a smartphone experience can be," said Llamas. "In addition, users have quickly warmed to Android, comparing it to iOS due to its ease of use and a growing mobile application storefront. Now that HTC and Motorola have leapt out in front with their own respective devices, other vendors such as Dell, Kyocera, LG Electronics, and Samsung will soon help grow the Android market."

Research by DPD Group last month found that the top five Android phones in the U.S. were, in descending order, the Motorola Droid, HTC Droid Incredible, HTC EVO 4G, HTC Hero and HTC Droid Eris.

It's Unanimous

Several other studies have shown strong upward momentum for Android, which is available on a wide range of devices on several carriers. Most recently, Gartner Research last month found that Android grew from a paltry 1.8 percent of the market in the second quarter of 2009 to 17.2 percent now. Market leader Symbian dropped from 51 percent to 41 percent, while number-two BlackBerry dropped slightly from 19 to 18.2 percent. Apple's iOS showed a slight gain in the Gartner study from 13 percent to 14.2 in the quarter to take the number-four slot.

A Piper Jaffray report also boded well for Android, giving 14.9 percent of the smartphone market through 2010, growing to 23.2 percent in 2012.

These projections are all in spite of the impossibility of knowing what breakthroughs are ahead for any of the companies in an age where four years is a lifetime.

"They look at the rolling momentum" of Android, said Gerry Purdy of Mobiltrax. "It reminds them of Microsoft and Apple in their heydey."

By Adam Dickter