rsz_mobilestuffBring your own device (BYOD); corporate-owned, personally enabled (COPE); and mobile device management (MDM) revolve around how consumers react in the mobile device market (think of Emma Watson), and how their behavior affects employers. IT research and advisory company Gartner (NYSE: IT)'s recent  report on device shipments revealed an increase worldwide for combined shipments of PCs, tablets, and mobile phones. Here's a deeper look at the report and what it reveals about shifting user behavior.

Gartner predicts worldwide device shipments will total 2.4 billion units in 2013, a 9 percent increase from 2012. Device shipments will continue to increase reaching more than 2.9 billion units in 2017. The mix, however, will change significantly.

Many consumers will user a tablet as their main computing device, instead of a personal PC, said Gartner Research Vice President Carolina Milanesi in a prepared statement. She added that tablets will be the device of choice for both work and play.

PC market declines, not temporary

The report predicts the PC market will decline in this year, with notebooks and desk-based units shipments falling 7.6 percent. And the decline is not temporary. PC shipments are forecast to fall from 315 million units in 2013 to 272 million units in 2017. Ultramobiles (tablets will full desktop operating systems, such as Microsoft's Surface Pro, as well as the smallest and thinnest laptop PCs) will help offset this decline, Gartner said, with combined sales of traditional PCs and ultramobiles showing a 3.5 percent decline this year.

Worldwide tablet shipments are projected to total 197 million units this year, a 69.8 percent increase from 2012 shipments. Why are more consumers purchasing tablets, instead of notebooks and desk-based units? Gartner Research Director Ranjit Atwal attributed the increase to consumer addictions to apps, cloud updates and lower prices.

"Growth in the tablet segment will not be limited to mature markets alone," he said. "Users in emerging markets who are looking for a companion to their mobile phone will increasingly choose a tablet as their first computing device and not a PC."

Android takes first, while iOS and Windows fight for second

As the smartphone market strengthens, so does Android's lead among operating systems (OSs) in device sales. Android shipments are expected to reach roughly 861 million units in 2013, increasing to 1.47 million units in 2017. But the battle's not between first and second -- it's between second and third.

Windows shipments are forecast to reach 354 million devices, while Apple's OS X and iOS combined for 293 million. The numbers between the two platforms become closer as the years go on. It will be interesting to see how this plays out.