Applications for the iPhone were originally developed by Apple and selected partners. With the release of the iPhone SDK, Apple opened up the field to other developers.

Applications, or apps as they are commonly known, cover everything from games to business, and movies to medicine.

By January 2010 over 140,000 apps, ranging in cost from free to $10 or more, were available for download from the iPhone App Store, and more than 3 billion downloads had been made. App can be downloaded directly from the device and also via iTunes on a computer.

Anyone can develop free iPhone apps, proviiding they have a Mac running OS X Leopard or better. Developers of paid apps are required to pay a $99 registration fee.

The iPhone SDK was announced early in 2008. Selected developers were allowed to utilize and test the developer's kit. With the release of iPhone 2.0, the SDK was released for developers to begin writing their own applications for the iPhone 3G.CNN: 'Pull My Finger' subject of court fight (February 17, 2009)

In August of 2008, rumors spread of a kill switch that could be covertly installed in the iPhone, capable of automatically deleting third-party applications at Apple's command. Apple CEO Steve Jobs later confirmed the existence of the kill switch, but insisted it would only be used in extreme cases (such as an application that installs malware on to the phone), and that no applications were currently on the "kill switch list."Engadget: Steve Jobs ...Confirms Kill Switch (August 11, 2008)

In February 2010, Nicolas Seriot, a software engineer the Swiss University of Applied Sciences, publicly warned that it is possible for iPhone apps to gain unauthorised access to user data, including search history, details from their contacts database, and their calendar and notes entries.http://news.cnet.com/8301-27080_3-10446402-245.html

This may open up users to spam and phishing attacks, and in the worse case may compromise sensitive data that is kept in notes. It is believed that some users keep sensitive information like bank accounts, or credit card numbers in their notes. Such vulnerabilities may also prove a problem for people who have legal obligations to keep certain data confidential, such as attorneys

He is quoted as saying: "Safari recent searches, YouTube history, and your keyboard cache give clues about your current interests. These interests are linked with your name and your e-mail addresses, your phone number, and your area. Harvested from large numbers of users, such data have a huge value in the underground market of personal data, and it must be assumed that Trojans are, in fact, exploiting this on the App Store."

Seriot said that he had alerted Apple about these issues a year ago.

Such concerns are not purely hypothetical as several apps have been previously pulled from the app store on similar grounds, including the game called Aurora Feint and Swiss road traffic information app MogoRoad. Users who downloaded the latter received calls from salespeople based on harvested information.

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