The App Store, in and of itself, seems to me to be a positive thing. It will simplify the process of finding, buying and updating Mac software, which is a chore even for power users, let alone novice computer users seeking simplicity. Personally, I'm sure I will end up using the store to find and try new software, and probably as my primary means of purchasing software. If it can do for my Mac apps what the iOS App Store did for mobile apps, such as keeping them updated and available across my Mac computers, I'm all for it.
So why am I concerned? After all, this store will only be one distribution system; you can still download apps from outside of Apple's closed ecosystem, and they made no mention of this changing. This is absolutely true. And there is no real problem with the App Store or modal computing so long as the platform itself remains open and Apple doesn't get obsessed with control the way they have with iOS devices. The iPad was really a paradigm shift in the way we, and Apple, think about computing; not as a mostly open, scalable system that is designed for flexibility, but as a simplified, modal, and highly controlled platform. This works fine for a specialized mobile device like the iPad, but not so much for a full-fledged computer.
What I don't want to see is the "iPad-ization" of the Mac platform, or computing generally. The day that I can't install an unapproved application on my primary computer is the day that I stop using that platform. Unfortunately, Apple has strong profit-driven motivations towards this model: it simplifies computing, so more people would adopt the Mac; they get a cut of the sale of apps; and they'd get full control over the entire platform, which makes Steve Jobs happy. The first point regarding simplification has its positive points, however in the process of simplifying computing, you run the risk of removing choice and making the computing experience less functional and more sterile. The last point, however, has potentially disastrous implications for computing as well as for consumers; problem is, the consumers have no idea what the implications are.
