In this lull before the storm of WWDC, when who knows what passel of new iPhones and OS X versions and such will be unveiled to a salivating audience, let's pause to acknowledge an Apple innovation that is proving its worth by its coming ubiquity: the App Store. Like, say, the mouse-driven windows-and-folders UI, the concept of a single-stop location from which you could download applications wasn't invented by Apple (the Lindows Linux OS had a desktop version, called "Click 'n' Run," way back in the early aughts, and I'm sure there are earlier examples), but Apple's implementation on the iPhone managed to capture the public imagination in ways that similar efforts didn't. The move is a huge part of what makes the iPhone interesting. Buying and installing applications on earlier smartphones was a confusing and cumbersome experience; now you wouldn't think of launching a new smartphone platform without one, as Palm will demonstrate with its upcoming Pre.
In fact, there are a number of App Store-esque offerings coming up. Verizon will be launching one for its Java ME-capable phones; I'm interested to see how that goes, as the fragmentation of Java ME profiles might make that tricky. And, speaking of Java, perhaps the most intriguing is the launch of the new Java App Store from Sun (soon to be absorbed into the Oracle collective). Users on both Windows and Mac OS X (which is the OS of choice of Java inventor James Gosling, if the video in that previous link is any indication) will be able to download and buy Java SE and JavaFX apps directly from Sun, which will provide a clearinghouse for all those Java developers looking to sell direct to customers. It could be a terrible flop, like all things Java desktop-y have been in the past, but it also good be pretty genius, particularly if the apps are interesting and/or cheap enough.
The interesting thing about all these app stores is that in each case it's a player in a somewhat different ecological niche running the store (and taking a cut). With the iPhone, it's the handset maker; with the Verizon store, it's the network carrier; with the Java Store, it's the company that owns the rights to the language itself. It will be interesting to see if the Java Store in particular is financially successful for Sun/Oracle, as scuttlebutt has it that the iPhone's App Store really exists to make the iPhone more attractive and salable than to make money in and of itself. And if it turns out that Mac users are willing buy Java apps directly from some kind of storefront application, well, why not Apple apps?