Dan Gillmor has an interesting report about a demo he recently saw of a zooming user interface– or ZUI– calendar (Datelens, developed by a U. of Maryland group led by Ben Bederson) for Pocket PCs. It seems to me that the number of zooming UI companies and products is growing rapidly: the number of attempts to bring ZUIs out of the lab have multiplied greatly in the last 12 months. So Groxis isn’t an outlier in its essential technical vision, though their sense of what Groxis will be able to do– in terms of helping users see the connections between things we usually compartmentalize– is unusual.

Will the appearance of more and more ZUI products in the marketplace be a good thing, or a bad one? Will they compete with each other, the way Apple and its clones did, giving customers more choice in the short run but leaving the market more vulnerable to Wintel in the long run? Or will they help each other?

I think a comparison to cities and industrial regions (like Silicon Valley) offers a useful lesson here. (What follows draws a lot on Steven Johnson’s Emergence and AnnaLee Saxenian’s work.) Why do specialized businesses tend to cluster together? Sometimes there are highly functional reasons: warehouse districts often are along rivers. But what accounts for a Jeweler’s Row or Restaurant Row, the concentration of galleries in SoHo, the Akihabara, the under 25-only bars stacked three high in Seoul’s Kangman area? On the face of it, it would seem that if you aren’t tied to a specific place, you’d want to locate away from competitors, because you don’t want to, well, compete with them. But it turns out that clustering makes sense because it means bigger crowds; because while you’re competing with the place next door, you also get extra business when they don’t have something and you do; because in large markets it allows for greater specialization; and because it generates a substrate of collective wisdom and experienced labor that benefits everyone. (You have to cooperate successfully to compete successfully.)

The ZUI world is more like a city or high-tech region. Here’s my guess about how it’ll unfold. Specific products doubtless will compete with each other: sooner or later, Apple or Microsoft will go head-to-head with Grokker. But most of the time, you’ll see zoomer-enabled software competing against non-zoomers: iPhoto versus whatever, GeoPhoenix versus whatever. The two really important things that will happen are 1) users will become familiar with the zooming paradigm, and 2) a body of expertise in designing, programming, and productizing ZUI products will grow. The user familiarity is important because it means that once I “get” a ZUI on my PDA, I’m more likely to use it in my Web browser, photo storage software, or desktop; my experience with iPhoto will make it easier for me to figure out a ZUI on a Linux box. Think of how keyboards have morphed into thumbboards, how cell phones use the same number pads found on regular phones. A familiar interface is a very powerful thing, and not just for psychological reasons: it breeds physical skills and pattern-recognition abilities as well. (This is one reason digital cameras so often borrow the form factor and control placement of film cameras. We know how to hold those kinds of cameras steady, to frame shots, to get predictable and satisfactory results.)

In other words, in the long run, a proliferation of ZUI products will be good for all ZUI products.