It's Sunday, only a half hour before the first NFL football game. As an addicted fantasy footballer, I'm on my computer configuring what my fantasy team lineup should be at the last minute. Using my 17-in. laptop computer, I rearrange my players using a friendly drag-and-drop interface.

Finally, it's kickoff. I've been waiting all week for the matchup against my loudmouth coworker. I turn on my 52-in. plasma TV to watch the game. However, this is not a normal football game. I'm watching a customized view personalized to my fantasy team.

There are four games with my fantasy players, arranged nicely in a 2-by-2 grid so I can watch them simultaneously or zoom in to one particular game for details. At the bottom of the screen, a sports ticker displays both the current and previous league scores. I'm winning, thanks to Matt Ryan's touchdown pass!

At halftime, I need to take my son to his soccer game, so I switch the view to my mobile phone. Cheering my son on from the sideline, I receive a text message. Previously down a few points, I've just been notified by ESPN that Calvin Johnson hauled in a 60-yard touchdown.

Opening the link in the text message, I'm watching the 30-second highlight of the touchdown on my 2.5-in. touchscreen phone. With one click of a button, I open a chat session to taunt my office mate. I'm miles from home, multitasking while watching a soccer game, but I haven't missed a beat for fantasy football.

While this fantasy football scenario might sound a bit futuristic, we have most of the pieces of this puzzle today. The convergence of three screens—mobile, computer, and television—is happening now. We can expect to see this football application, and many others like it, seamlessly integrated across all mediums in the not too distant future.

Challenges Ahead
So what's preventing mass development of multi-screen applications today? It's certainly not the adoption of these mediums. According to Research and Markets, nearly 80% of homes had a computer at the start of 2009, while the wireless association CTIA estimates mobile phone penetration in the U.S. at 89% as of June 2009. In addition, Nielsen estimates the penetration of televisions in U.S. households was 98.9% in 2009.

The three devices are all clearly in the home (with a significant overlap), meaning that it's not a question of penetration, but rather an issue with different technologies. To successfully converge the three screens and have a single environment for the delivery of multi-screen applications, we need to consider screen sizes, the user interface, application platforms, network speeds, and protocols. Desktop PCs and mobile phones already share some of these elements, like an Internet Protocol (IP) network, but little else.

Screen size and user interface are the most obvious differentiating factors to the end user, and they will continue to differ until someone figures out how to fit a 52-in. display into my pocket. This means that for developers building multi-screen applications, the selection of a quality rendering technology becomes important.

A rendering technology can separate the presentation of an application from its logic so its presentation can be optimized across any intended device. A good rendering technology also understands the differences in a device's user interface and navigation capabilities to appropriately modify the application for interactivity on any form factor.

Application platforms are more important to the developer than they are to the end user. Arguably, the most limiting device for the application developer is the television. The basic TV does one thing well; i t plays video. Otherwise, it's difficult to build compelling, interactive applications for the largest of the three screens. Set-top boxes, game consoles, and other television accessories are attempting to change this and provide an environment for applications, but we're very much still in the early stages.

Meanwhile, mobile is attempting to catch up with the PC and attract application developers to write code for the small screen. One of the big problems, however, is that there are too many platforms to choose from, with numerous mobile development platforms such as iPhone, Android, Windows Mobile, LiMo (Linux Mobile), Symbian, J2ME (Java), and BREW, to name just a few.

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