They say "content is king." But, "context is kingier" when it comes to designing great smartphone and tablet mobile apps. Don't make the mistake of thinking that mobile app design is just about a smaller screen size or choosing the right development technology. Content and context are both important to designing great user experiences, but mobile amplifies context on five critical dimensions: location, locomotion, immediacy, intimacy, and device. Understand each dimension of Forrester's mobile context to design mobile apps that will make your users say "I love this app!"

Forrester LLIID: Location, Locomotion, Immediacy, Intimacy, And Device

• Location. People use apps in an unlimited number of locations. And not all places are the same. A user may be in a quiet movie theater, at home in the kitchen, on a train, or in the White Mountain National Forest. Contrast this with desktop computers, stuck in places such as an office cubicle, home office, or kitchen. Laptops provide some mobility but are larger and less able to provide the immediate access of instant-on mobile devices such as smartphones, eReaders, and tablets. Location is a key dimension of context, driving different needs for users depending on where they are. Fortunately, GPS-equipped smartphones can use a geodatabase such as Google Maps to determine precise location.

[As promised, here's the first in the series about the tech industry's drive to reduce complexity.]

Remember the magic number? It's the one thing from Psych 101 that you should recall, since it pertains to memory. The brain has an upper limit on the number of chunks of new data it can stuff into working memory at one time. The number is around seven, plus or minus one or two depending on the person and the task. It's the limitation that makes the old game Simon challenging, and that bedevils us when we try to remember a phone number that someone just told us.

The magic number is one way in which the human brain tries to trim down complexity. Another more recent discovery is the brain's fuzzy boundary between literal and metaphorical statements. Attach a candidate's resume to a heavy clipboard instead of a light one, and the interviewer is more likely to treat the candidate seriously, because the resume seems somehow weightier.

Countless other examples exist where the brain takes shortcuts, filters information, and otherwise simplifies the constant, complex stream of perceptions, thoughts, feelings, and actions that would otherwise turn into a "blooming, buzzing confusion." We're not stupid creatures, but the machine that grants us powerful mental capabilities also puts limits on them.

The Death Star Would Be Great If I Could Figure Out What All These Buttons Do

During last August's Agile 2010 conference, I attended a session that used a board game to simulate the collaboration between developers and UX professionals. The object of the game was to coordinate the schedules of these two groups, who normally follow the beats of different metronomes. On top of that basic timing challenge, unexpected events complicated this dance between development and UX.

While this session does show a novel application of serious gaming (one of my favorite topics, in case you hadn't noticed), the interesting aspect of this session is that it happened at all. Until recently, UX was not a major concern for Agilists – or most people developing software, for that matter. The phrase, "And then we'll throw a UI on top of it," summarized the indifference of all too many development teams to UX concerns.

In the last few years, many teams have learned a new attitude. Instead of treating UX as a tarpaulin, thrown over the application to clumsily hold it all together, UX is as much a part of the system as the technical architecture or the application logic.

If you're still baffled, flummoxed, or concerned about Facebook's now-infamous privacy policies, here's a handy chart from The New York Times. (Thanks, Madiha, for the pointer.) While the diagram retains a neutral tone, it's hard to read the phrase 50 settings with over 170 options without having a "What the hell?!?" moment.

In defense of Facebook, they're no worse than many technology companies that devise confusing UIs, full of knobs and dials that users don't understand or use. These companies are still to blame for creating the circumstances in which a confusing UI is hard to avoid, so they're not completely blameless.

An apology to future generations
Here's where we venture into the idiosyncratic sub-culture of the tech industry, which is hard to understand if you've never been part of it. In spite of having big development budgets, a staff of seasoned professionals, and months to build a useful product, tech companies repeatedly build software that begs the question, "Daddy, why is your product so hard to use?" (Even weirder: usability is often inversely proportional to the price.)