Mac sales climb as rivals lose U.S. share

Kitagawa resisted the term "cannibalization" for what tablets are doing to PC sales, saying that people weren't necessarily buying a tablet instead of a personal computer, but were buying a tablet now, then postponing upgrading the home machine.

"Some consumers are extending the life cycle of their PCs," she said. "They're holding onto the PC, but spending their discretionary income on something else, whether that's a media tablet or a game console or just eating out more."

Kitagawa said the decline in sales of traditional PCs will likely accelerate in 2011 as tablet prices drop with the expected introduction of Android-based devices that undercut the iPad's price.

IDC made the same prediction.

"This situation is likely to persist in 2011, if not worsen, as a wave of media tablets could put a dent in the traditional PC market," said IDC research director David Daoud in a statement Wednesday.

Gartner and IDC separate tablet sales from personal computer numbers, but if they put the iPad in the PC pigeonhole -- as they do netbooks, for instance -- Apple' would likely have captured the world's No. 3 spot.

Other analysts, like Brian Marshall of Gleacher & Co., have estimated worldwide iPad sales in the fourth quarter at 6 million, Mac sales during the same period at over 4 million. The total of 10 million would move Apple up to third place in IDC's global top five, behind only HP and Dell. The same 10 million would put Apple in fourth place on Gartner's list.

Apple will release its official Mac sales figures next Tuesday, Jan. 18, when it releases its fourth-quarter earnings report.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@ix.netcom.com.

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