Apple on Thursday loosened rules for applications built for its iPhones, iPods, and iPads in a move that promises to make it easier for friends and rivals to get programs on the popular gadgets.
The California company also pulled back the curtain on its long-private review guidelines that third-party applications must meet to get into Apple's online App Store.
"We have over 250,000 apps in the App Store," the developer guidelines said. "If your app doesn't do something useful or provide some form of lasting entertainment, it may not be accepted."
The more open stance was expected to appease software makers who have complained about constraints on code for Apple gadgets and the mystery shrouding the App Store vetting process.
"It is a softening by Apple to the developers," said Gartner mobile analyst Van Baker.
"Before, developers felt they were submitting applications into a black hole and had no idea what criteria were applied. Now, in refreshingly frank language, they have an idea of the criteria applied," he said.
Apple is by no means throwing its doors completely open to developers, but they are showing flexibility and communicating more directly with software makers, according to the analyst.
Third-party applications are key to the popularity of smartphones.
"With all the high-end smartphones, if you don't have applications the devices don't have much appeal," Baker said.
The new licensing rules would allow developers to write programs with Adobe's Flash video software and then convert them into the iOS format acceptable to Apple.
Apple has banned the use of Flash on the iPhone, iPod Touch and iPad and Thursday's revision of the rules still does not permit the use of Flash on the devices.
"A developer can start in Flash and end up in code acceptable to Apple, but that doesn't mean you can run Flash on the iPhone or iPad," Baker said. "You would need to download the Flash Player on the device, and you can't do that."
Instead of Flash, Apple devices support video built using HTML5, a fledgling software format created by a group of technology firms including Google and Apple.
Apple left plenty of room for discretion in the application vetting process.
"We will reject Apps for any content or behavior that we believe is over the line," Apple said in its guidelines.
"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 California company said it had listened to developers and took much of their feedback to heart.
"In particular, we are relaxing all restrictions on the development tools used to create iOS apps, as long as the resulting apps do not download any code," Apple said. "This should give developers the flexibility they want, while preserving the security we need."
Apple mobile gadgets run on an iOS software platform. Blocking the download of code is seen as a security measure to prevent hackers from slipping malicious software onto devices.
The looser rules should make it easier for software makers to craft similar versions of App Store applications for smartphones that compete with iPhones.
It appeared as though there was also the potential for Apple gadgets to be opened to applications serving ads from Google or Admob, which is owned by the Internet powerhouse.
"This is great news for everyone in the mobile community," Google vice president of product management Omar Hamoui said in a blog post. "We believe that a competitive environment is the best way to drive innovation and growth in mobile advertising."
Adobe shares soared on Wall Street on Thursday, gaining 12.11 percent to close at 32.86 dollars while Apple shares were up 0.06 percent to 263.07 dollars.