There is a free Lite Edition of 2 Across available in the App Store, an exclusive shop on the iPhone where users can download applications, but the full version costs $5.99 and has been on sale since July. Apple gives its freelance developers 70 percent of the revenue from each download, and Ms. Block has been able to double her income as a graduate student, making as much as $2,000 a day.

“I didn’t really know what I was doing,” Ms. Block told The Observer over the phone. “I just made this application for me so I could take the puzzles with me. But I was really surprised by how many people were downloading it.”

The iPhone platform has become a creative (and sometimes lucrative) playground for developers. Since Apple released the device in June of last year, everyone from Facebook to tiny start-ups and tech freelancers have been developing new applications to take Web sites, services and games on the go. At Apple’s press event last week, CEO Steve Jobs said that users have downloaded more than 100 million applications onto their iPhones. New York seems to be the perfect incubator for application ideas. New Yorkers wait in line a lot (whether for security checkups or Jamba Juice); get bored on the subway; and are simply out of their homes a lot, away from their primary computers. There are endless possibilities for developers to tap into our particularly busy lifestyles.

Daniel Budiac, a Web developer who lives and works in the East Village, created a Web-based application so he and his fiancé could keep track of when his dog, a 4-year-old puggle named Beta, went to the bathroom. They answer two questions, “Did she pee?” and “Did she poo?” and then finish the entry by pressing the “Good girl!” button. A note appears on both of their iPhone screens letting them know when and what Beta did on her last walk, and also posts the updates to the short-form blogging platform Twitter so that they’re both aware of her … bowel movements.

Mr. Budiac told The Observer that the application took an hour to create.

DESIGNING FREE, one-off Web-based applications like Mr. Budiac’s Walk a Dog are usually cakewalks for developers. They just need to make a special Web site designed and scaled for the iPhone, which can then be accessed through Safari, and voilà! But applications like Ms. Block’s 2 Across, which must be downloaded onto the device, are slightly more complicated. Apple is confounding developers further by gagging them from sharing details about their code, which is comparable to a bunch of cooks working on similar recipes for tomato sauce, but not being allowed to discuss their ingredients.

Here’s what happens: Before developers can download the SDK, they have to agree to the terms of a restrictive nondisclosure agreement (NDA), which legally bans them from sharing programming tips, discussing code or asking questions of one another in forums, on blogs or over e-mail.

“There’s a lot of new information to process all at once,” Ms. Block explained over the phone. “You think, you know, how can I make it do this? And if you can’t find it immediately in [Apple’s] documentation, there was nowhere to go. It was impossible to figure it out.”

When Apple released the iPhone, developers were immediately inspired by the new platform. But Apple initially decided to close the platform—they could write applications that would run on the iPhone Web browser, but not applications that could be downloaded onto the device itself. This meant that iPhone users without Internet access—on the subway, say—would not have continuous access to applications.

On March 6 of this year, after an uproar from developers, Apple CEO Steve Jobs stood in the company’s Cupertino, Calif., headquarters and announced that the company would open the iPhone to developers and release the SDK. In his signature black turtleneck and baggy jeans, he warned that there would be some restrictions to what Apple would allow into their new App Store (no porn or “malicious” applications) but noted that “we have exactly the same interest as the vast majority of our developers,” he said, “which is to get a ton of apps out there for the iPhone.”

Developers were required to accept the terms of the NDA before they could download the software needed to create applications. NDAs are typically issued in software development when products are in the early stages, to fend off media speculation and competitor copycats. Developers expected to be free of the NDA once Apple released their new version of the iPhone, with the App Store installed, in July. But infamously tight-lipped Apple has kept the restrictions in place and hasn’t explained why.

After several e-mails to Apple, a representative called The Observer and said the company has no comment. “We don’t discuss the NDA,” he said.

But developers certainly are. “Fucking NDA” has become a battle cry on Twitter.

Justin Williams, 25, a developer for Second Gear, created FuckingNDA.com in late July to display his comrades’ frustration with Apple.

The site feeds in Twitter and del.icio.us links that include the phrase “fucking NDA.” Here are just a few of the site’s acerbic “tweets”:

“mdhughes: Sigh. Fucking NDA, no code samples showing use of [REDACTED], and minimal documentation. Thanks, Apple.”

“lieven: Anyone know how to resize an image on [REDACTED] without losing EXIF data? FUCKING NDA!”

“HelgeG: apple, lift the fucking NDA already”

“It hinders me from actually wanting to jump into the iPhone thing full throttle,” Mr. Williams said. “People keep saying, ‘I’m hitting this wall, has anyone ever done this?’ There’s no legit ways for us to fix the problem and ask around for help. I can spend a day working out a problem, and you don’t want to be reinventing the wheel every day, trying to solve it.”

Mr. Williams said he has seen developers discuss coding secrets through Apple’s online developer forums. “I don’t think they’re necessarily spending a lot of time policing this,” he said. “But you don’t want to be the guy they make an example of.”

THIS SUMMER, Julio Barros, a 44-year-old freelance developer who lives in the East Village, organized the New York iPhone Software Developers Meetup through social networking site Meetup.com. He said all the developers have been careful about what they say at the meetings and mostly use it for networking.

He said the developer community is used to being able to ask each other for help in public online forums, and having restrictions makes them feel stifled. “It’s just working alone in the dark a lot. It can truly hamper development.”

“I wish [Apple] would come out and just explain why this is like this,” said FuckingNDA’s Mr. Williams. “A lot more developers would at least understand if maybe it was for trademarking or to patent things. But the fact that they are just staying silent about it doesn’t help.”

Some developers haven’t had much trouble with the NDA and think the community is just overreacting. Joshua Keay, a software developer for Magnetism Studios, said the NDA “hasn’t been a problem for us whatsoever.” They created a few applications for the iPhone, including CityTransit, a downloadable guide to the city’s subway system, and the TileSudoku game.

“Frankly, people like to get all worked up,” Mr. Keay said. “I think Apple is by and large pretty good about the craft and just want greater quality control. People just like to sound off about anything and the Internet, on Twitter, is an easy place to do it.”

Buzz Andersen, a former engineer for Apple who now works as a freelance developer in the Lower East Side, said Apple probably isn’t being malicious against developers—they’re just ignorant. “People in the developer community, they kind of take it for granted that something like this is obvious to Apple,” he explained. “They just don’t really think to communicate with developers or outside people when it would actually be a good thing to defuse a lot of tension. I can honestly believe they would’ve never expected this kind of furor. I could imagine them saying, ‘Well, they’re all competitors competing with each other, so whatever.’

“The good thing about Apple, though,” Mr. Andersen added, “is once something like this really starts to become a problem, they are generally really quick to rectify it. It’s just that sometimes it has to reach a sort of fever pitch in media coverage. Since it’s so secret, the public is not always even aware of what developers can and can’t do with the SDK. So developers can get into this weird situation where reviews on the App Store, people will say, ‘This app would great if only it had this; why doesn’t it do this?’ But it’s weird,” Mr. Andersen said. “They can’t explain the finer reasons and boundaries of something.” Perhaps they just need to respond: “Fucking NDA.”