Thanks for a great piece, Kathleen. I’m excited about getting an iPad too (though I won’t have one tomorrow :'( ), though I feel a lot of the worries you’ve cited here.
I’ve worried especially about Zittrain’s point, which Alex Payne nicely called a “tinkerer’s sunset”. http://al3x.net/2010/01/28/ipad.html But in the months since the iPad was announced I have become increasingly fond of thinking about the issue in the following way: New waves of technology tend to shift the strata of interesting hacking up a level. Programming languages made hardware hacking a bit less interesting; the web made OS-level hacking a bit less interesting; etc. I tend to think that not much is lost in each of these steps of a progression, and generally a lot is gained. It’s possible that there’s another layer of hackability that hasn’t really come into focus yet, one that tech like the iPad – with its decreased hackability at strata that current-day geeks have grown accustomed to – may cause to emerge.