If you’re not already targeting a tablet audience, you may want to start doing so, because in a few short years it’ll be larger than the PC industry.

That’s the message the research company Gartner has underlined in its latest report on the worldwide computer market, which shows a significant slowdown in the traditional PC market but—simultaneously—predicts a major jump in worldwide tablet shipments, coinciding with ongoing mobile growth.

More key points from the report:

An ongoing decline: In 2013, Gartner predicts that PC-based models, such as desktops and notebooks, will decline by 7.6 percent to 315 million units shipped worldwide. At the same time, the tablet market, which was not a major player until 2010, is expected to hit 197 million in 2013 and 468 million by 2017. (And that’s nothing compared to mobile phones: Shipments of devices like smartphones are expected to top the 2 billion mark by 2017.) Emerging markets will play a major role in the growth of worldwide tablet shipments. “Growth in the tablet segment will not be limited to mature markets alone,” Gartner’s Ranjit Atwal noted in a press release. “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.”

The most popular OS? You might be surprised. While Windows remains a force in the desktop world, Android was already the world’s most popular operating system in 2012, and its lead is only expected to grow significantly by 2017, to nearly 1.5 billion devices worldwide, based on Gartner estimates. Windows, in comparison, would be installed on 570 million devices by 2017 and iOS on 504 million. “Android is going to get to volumes that are three times those of Windows,” says Gartner researcher Carolina Milanesi, who spoke to The Guardian. “From a consumer perspective, the question becomes: What software do you want to have to get the widest reach on your devices?”

The long-term effects: This could have multiple effects on both usage patterns and the manufacturers themselves. Among other things, margins will decline, consumers will use the cloud more often, and new models will emerge for different segments of the market, such as prepaid models or more targeted applications. “The trend towards smartphones and tablets will have much wider implications than hardware displacement,” Milanesi said, according to the press release. “Software and chipset architecture are also impacted by this shift as consumers embrace apps and personal cloud.”

From responsive design to apps, how has your association adapted to the changing computing climate? Let us know your thoughts in the comments below.