Interviewing a fellow analyst is always rewarding. This morning, I had the pleasure of speaking with John Jacobs, director of notebook market research at DisplaySearch, which is part of the NPD Group. We talked about the outlook for an emerging category that has many names in the industry – e.g. mobile Internet devices or ultra-mobile devices – and comprises everything from netbooks to tablets to e-book devices to gaming platforms.

These devices come in a range of sizes and form factors, but they share a number of important characteristics, including growing feature sets, processing power and reliance on wireless networks to deliver content. I’ll be looking at the confluence of devices and networks in my next report.

The key issue we discussed is oldie but goodie that’s resurfaced again in the past year: how many devices are consumers willing to carry with them? As smartphones evolve into veritable Swiss Army knives, do they obviate the need for netbooks? With a fully functional Kindle app available for the iPhone, do iPhone owners need to purchase a separate e-book device?

These questions ebb and flow with the evolution of the device cycle. Mr. Jacobs’ research suggests that consumers want fewer, more capable devices rather than multiple single-function gadgets, but the challenge with multifunction devices is always one of performing every function well (or at least well enough).

Interestingly, the reaction of consumers varies considerably by market. In developed markets like those in North America, Western Europe, Japan and South Korea, DisplaySearch has found that consumers buy netbooks as a secondary device (to an existing laptop or desktop PC) for specific usage situations (for example, Mr. Jacobs noted that in Western Europe, buyers use netbooks as substitutes for portable DVD players). In emerging markets, by contrast, netbooks sell at a far more accessible price point than more capable laptops, so buyers are willing to sacrifice features and performance just for the ability to purchase a portable computer.

Look for the complete interview transcript in the coming weeks.

FierceWireless has a story today that caught my eye. It focuses on the reasons why Amazon is no longer selling Sprint-powered Kindles and has instead turned to AT&T for wireless network support for its e-book device.

The justification is simple: Amazon is a global company, the content it sells for the Kindle (books, newspapers, magazines and blogs) is created and consumed worldwide and the Kindle device itself is all about mobility. Consequently, Amazon needs a single network technology that will support international roaming and seamless content downloads anywhere in the world.

Amazon’s decision has a number of implications, some more obvious than others. On the more obvious side, it’s clearly a big blow to Sprint, already the most troubled of the tier one US carriers.

On the less obvious side is the message it sends about the different ways consumers are accessing content now and how this consumption is trending for the future (the Washington Post has a good piece on the high expectations for e-book-related sales during the holiday season). For example, we’re well acquainted with the impact of mobile phones, and smartphones in particular, on content and marketing, but the rise of e-books and netbooks is expanding the notion of what constitutes a mobile device.

E-book device sales are small today, no doubt about it, but they are growing – fast. In August, the Association of American Publishers reported Q2 2009 e-book sales in the US rose to $38 million, more than triple from the second quarter of last year. Globally, research firm In-Stat predicts massive growth in e-book shipments over the next several years, from just under one million units in 2008 to 28.6 million in 2013. The netbook market is already much larger. ABI Research predicts that 35 million netbooks will ship in 2009 alone.

The expansion of mobility on the device side has been matched by growing broadband Internet access everywhere. But in both cases, the story is less about the underlying technologies and more about the kinds of interaction they will facilitate. Mobile devices + ubiquitous Internet access = new possibilities for marketers to reach consumers in a variety of ways and on a variety of devices. Sound like a topic worthy of an eMarketer report? Hope so, since that’s where I’ll be turning my attention next.