(AP) -- Apple Inc. gave software developers on Thursday the guidelines it uses to determine which programs can be sold in its App Store, yet it reserved for itself broad leeway in deciding what makes the cut.
The move follows more than two years of complaints from developers about the company's secret and seemingly capricious rules, which block some programs from the store and hence Apple's popular iPhone, iPad and iPod Touch devices.
The guidelines go some way toward addressing those complaints and broadening the discussion about Apple's custodianship of the App Store, but they leave much for the developers to figure out.
"We will reject Apps for any content or behavior that we believe is over the line. What line, you ask? Well, as a Supreme Court Justice once said, 'I'll know it when I see it'. And we think that you will also know it when you cross it," the guidelines say.
Earlier this year, Apple forced the creator of a comic-book version of James Joyce's novel "Ulysses" to alter some panels featuring nudity, echoing the censorship debate in the 1920s and 30s, when the novel itself was banned in the U.S. for obscenity.
In the guidelines, Apple draws a line between broader expressions of freedom of speech and the App Store.
"We view Apps different than books or songs, which we do not curate. If you want to criticize a religion, write a book. If you want to describe sex, write a book or a song, or create a medical app," the guidelines say.
Apple also says it will block applications that don't do "something useful or provide some lasting entertainment."
"We don't need any more Fart apps," Apple said, referring to prank programs that let off noise.
Despite the restrictions, or perhaps because of them, Apple's store has been a runaway success since its launch in 2008, and now has more than 250,000 applications for its popular devices.
The App Store's chief competitor, Google Inc.'s Android Marketplace, has few restrictions for developers. That's been welcomed by developers, but has also led to a flood of low-quality applications and even some that prey on buyers. Security firm Kaspersky Lab said it found one media player application that secretly sends text-message payments - which get added to phone bills - when installed by Russian phone users.
Apple has previously named some broadly worded restrictions in its developer agreement, but the agreement itself is confidential. In the guidelines, which offer a bit more details, Apple warns about publicity as well.
"If your app is rejected, we have a Review Board that you can appeal to. If you run to the press and trash us, it never helps," the company said.
Also Thursday, Apple also said it will lift restrictions imposed earlier this year on using third-party development tools that "translate" code written for another platform. That means developers who work in Adobe Systems Inc.'s Flash or Oracle Corp.'s Java language can convert their programs into iPhone apps without rewriting them.
Adobe shares jumped on the news, rising $2.83, or 9.7 percent, to $32.14 in morning trading. Apple shares rose $3.26, or 1.2 percent, to $266.18. Google shares gained $8, or 1.7 percent, to $478.58.
Explore further: Sony surprises with first quarter profit