The next great "killer app." could be a fundamental improvement in the way people who are separated over time or distance can communicate their ideas to each other. Precedents abound throughout history: the printing press, telephone, broadcast radio, television, the World Wide Web. Each of these innovations changed the structure of how ideas are communicated within society, by supplying a new, or newly economical, distribution mechanism for ideas.

The most interesting software or hardware platforms are the ones that revolutionize the way people communicate. Pen-based PDAs and tablet-PCs have the potential to enable such a transformation, but only if their mobility, ubiquity and stylus-based input are used to communicate in ways that are beyond the reach of the desk-bound mouse and keyboard user.

One way to exploit this potential is to ask the question: "How do people communicate with each other casually, at the moment they create ideas?" Such casual communication is much more important for idea creation than are formal presentations after the fact.

When people get together in person, say at a restaurant, and brainstorm new ideas, they generally talk over a piece of paper, drawing rough "napkin sketches" while talking and gesturing to convey their thoughts. In a more academic setting, the napkin is often replaced by a large whiteboard, but the paradigm is the same: structures, objects and processes over time are sketched out by a collection of pictures that are developed over time. In this way, many types of structural elements are effectively communicated, such as containment, sequence, conditional dependency, cyclic flow, geometric relationship, and so forth.

In contrast to these sorts of informal methods, professional presentation tools such as Flash, Shockwave, Alias/Maya, are only marginally used for idea generation. These tools are well designed for creating polished presentations off-line. Yet the very qualities that make them so well suited for fine tuning presentations works against them as idea generation tools.

This difference between casual idea creation and professional presentation design can also be characterized by asking the following question: "would domain experts use this tool, or would they hire someone else to use it?" For example, two physicists in a restaurant or a seminar room would not hesitate to pick up a pencil or dry erase marker and start sketching their ideas. However, they would be much less likely to brainstorm with Flash or Shockwave, or even to know how to author with these tools. In reality, if a physicist needed to use these more polished tools to give a professional presentation, he or she would most likely hire a young graphic designer who had spent a summer learning how to author in Flash.

We find the same situation within many professions. Were we, for example, to replace "physicist" with "football coach" in the previous paragraph, we would find that the same situation portains.

Currently, the only truly widely used computer-based tools for immediate and casual communication of ideas are email and instant messaging. It is interesting to note that these tools use only text; our networked society is still connected by a paradigm of remote communication that predates computers by hundreds of years!

With the right software, mobile pen-based interfaces could capture the dominant cultural position now taken by email and instant messaging - to become a tool that provides people with a way to communicate over distance and time which is richer and more powerful than text alone.

I think the key to effecting this is in allowing people to capture the immediacy and power of rapid creation of "drawings over time" in a way that can be used for networked communication on mobile stylus-based devices.

My interest in this area is in the opportunities for long term educational transformation: should mobile pen-based platforms become an enabler of a new language for idea creation, then they can lead to an expansion in the definition of, as well as the teaching of, literacy. The instantaneous expression and networked sharing of dynamic new ideas on this platform can well become a mainstay of K-12 education and beyond. Eventually, the ability to rapidly exchange rich and dynamic ideas on mobile and "casual" computing platforms could come to be seen as the birthright of an educated citizenry.