Under pressure from developers, Apple has dropped the controversial NDA clause previously imposed on its iPhone OS. Many developers are expressing their happiness on Twitter and elsewhere online, sometimes in pithy language.

Admitting that the non-disclosure agreement [NDA] for developers of apps for the iPhone's App Score is creating a "burden for developers," Apple is now abandoning the agreement for released software.

Thanking all who gave "constructive feedback" about the controversial clause in the iPhone SDK, Apple has posted a message on its developers' Web site explaining that the NDA was established "as one more way to help protect the iPhone from being ripped off by others."

Yet "the NDA has created too much of a burden on developers, authors and others interested in helping further the iPhone's success, so we are dropping it for released software," according to Apple.

This doesn't mean, though, that Apple will impose no agreement whatsoever on developers. "Developers will receive a new agreement without an NDA covering released software within a week or so," Apple's letter says. "Please note that unreleased software and features will remain under NDA until they are released."

Developers annoyed by the NDA had been peppering Apple, message boards, and Twitter with their views.

Among other problems caused by the NDA, developers had trouble figuring out ways to meet to compare code samples -- and talk about ways of getting their software into the App Store -- without violating their deals with Apple.

"It looks like the talks have been changed to avoid the iPhone NDA. At a future meeting, if we can verify each attendee has agreed to the NDA (by having them log into the iPhone Dev Center), do you think we'll be able to discuss iPhone development?," suggested one developer, in a post to the Reston CocoaHeads site.

Frustration with the NDA got so strong that Second Gear set up a message board on its Web site whose title invoked a certain non-repeatable gerund.

Clearly, lots of iPhone developers were thrilled to learn that the NDA is history. "Let us have a moment's silence for the phrase 'F------ NDA.' For it has passed on but it will never be forgotten by Twitter users," Twittered one developer.

"Holy [other Nixonian expletive deleted]! I come back from holidays and the f------ NDA is lifted! Rock on!" exclaimed another.

But although Apple's blog doesn't directly address the plight of developers whose iPhone apps have been turned down by the App Store, it seems as though the NDA will stay in effect on their software -- since applications such as Podcaster and Murderdrome haven't actually been released by Apple.

As BetaNews reported in September, Apple looks likely to be using the NDA clause to keep spurned developers from talking about the App Store's rejection of their applications.

The full text of Apple's letter to developers follows: