Buy an iPhone, iPod Touch or iPad, and you get to choose from thousands and thousands of “apps”: software that ranges from full-blown business applications to games to novelty items. But before an app can make it to your iPhone, it has to make it onto the virtual shelves of the App Store… and that means convincing Apple that the app is worthy of inclusion.

Apps are rejected all the time for a wide range of reasons – some of them more opaque than others. And that often leads to controversy… and, sometimes, embarrassment for Apple, when its gatekeeping looks less like protecting the user experience and more like arbitrary capriciousness.

The latest glitch came when online cartoonist Mark Fiore won the Pulitzer Prize (a watershed moment for doodlers unaffiliated with newspapers, by the way). It emerged that just a few months earlier, Apple had rejected his NewsToons app for “ridiculing public figures” – a rule that covers much if not most of the world of satire, and a big swath of civic conversation. (And it’s not the only time arbitrary rulings on cartoons have caused consternation.)

The Association of American Editorial Cartoonists sent Steve Jobs an open letter raising free speech concerns. The App Store is “becoming one of the primary ways people publish news and information,” they said, and “with that innovation comes new responsibility.”

That one sentence hints at a much bigger issue, one we’re all going to have to deal with.

* * *

More and more of our online social activity is happening in “private” places – that is, sites and services that are owned and controlled by companies. The more happens, the more those private places begin to look like civic spaces. Yet those spaces are governed by corporate gatekeepers – accountable not to us, but to the owners of the sites, services and products mediating that experience.

Maybe in an ideal world, the market would pressure those owners to be more responsive to participant communities – or risk losing them to a more open and accountable competitor. But there’s a self-perpetuating cycle with large networks like, say, Facebook. Once they reach a certain size, their market share is a market differentiator; of course you’re going to participate on Facebook, warts and all, because that’s where everyone you know hangs out. And they all hang out on Facebook because that’s where all their friends – including you – hang out.

Besides, you have a ton of stuff locked in there: photos, videos, months or years of notes, updates and application data – not to mention your network of friends. It’s not like you can pull up stakes, leave Facebook and have all that stuff follow you.

Facebook has this huge market share because they’ve built something compelling. They’ve made a lot of things very, very easy – from maintaining a decent-looking social profile (compared to the god-awful mess over on MySpace) to keeping tabs on what your friends are up to. It’s not as though they haven’t earned a big chunk of market share.

Same with Apple. The iPhone is a glorious device, as is the iPad that followed it. There’s good reason for Apple’s reputation for making spectacularly well-conceived, well-designed products – and their large audience makes them an attractive platform for developers.

But here again, there’s a vicious (or, if you own Apple stock, virtuous) circle at work. Developers flock to the iPhone in part because there’s a large user base. Users flock to the iPhone in part because there’s a massive selection of apps, built by those developers. The more users, the more apps being developed; the more apps, the more users drawn to the iPhone.

In each case, a company has gained enough market share to make it far more difficult for a competitor to pose a threat. In each case, they’ve gained enough market share that their gate-keeping decisions have a significant impact on the flow of information and conversation. And in each case, those companies have at times treated that impact capriciously and arbitrarily – falling fall short of a reasonable standard of accountability.

What can we do at that? I’ll look at one alternative in part 2.