You might say sales of personal computers are a bit sluggish, all around, with consumers seemingly preferring to spend their money on tablets. Even Apple Mac sales, which have been climbing since 2000, reversed in 2012.

Tablet PC shipments are expected to reach more than 240 million units worldwide in 2013, easily exceeding the 207 million notebook PCs projected to ship, according to NPD.

Tablet shipments will grow 64 percent in 2013, compared to 2012.

As the variety and demand for new screen sizes increases, so will market growth in emerging markets. Having passed EMEA in 2012 to become the second-largest market for tablet PC shipments, China will have 27 percent of the global tablet market in 2013 with shipments of 65 million units, driven by small local brands.

North America, however, will remain the largest market with a 35-percent share (85 million units) in 2013. In both China and North America, tablet PC shipments surpassed notebook PC shipments in 2012.

Google’s Chrome-based models generally have been slow sellers, but accounted for 5 to 10 percent of Acer U.S. shipments since being released there in November 2012, President Jim Wong said.

Sales figures for Windows 8 are perhaps a disappointment as well. are far from encouraging: Windows 8 has only a 2.26 percent market share as of the end of January, 2013, trailing not just Windows 7, Windows XP, and Windows Vista, but even Mac OS X 10.8, according to NetApplications.

This doesn't bode well for the ultimate success of the operating system, some might say.

None of that should be surprising, though. How people use PCs at home is changing, with most likely to shift to a "shared" device model, with the personal devices becoming the smartphone and tablet.

The change is that although most homes will keep a PC for content creation, on a shared basis, spending that once went for "personal" PCs might be shifting to tablets. That means the replacement PC market will shrink.

That implies a market where most people will use "personal" tablets as the primary Internet appliance, while the shared PC gets used when people have to create content.