Applications

The phone has several applications located at iPhone's "Home" Screen, including YouTube. It will stream the videos over Wi-Fi and/or EDGE after encoding them using QuickTime's H.264 codec, to which YouTube has converted about 10,000 videos. They are expected to convert the entire catalog by Fall 2007. As a result, the YouTube application on iPhone can only view a certain selection of videos from the site.[citation needed]
At WWDC 2007 on June 11, 2007 Apple Inc. announced that the iPhone will support third party "applications" via the Safari web browser, that share the look and feel of the iPhone interface. The applications must be created in Ajax or JavaScript to maintain device security.[22] The iPhone cannot install full programs from anyone but Apple.[23] Steve Jobs has referenced full programs being created by parties other than Apple[24][25]
Analysts also claim that iPhone lacks any type of firewall, which some experts claim is posing a data security risk.[26] It is not confirmed by Apple or by independent analysts that used the actual device for tests that it doesn't have a firewall. Daniel Eran writes: "Dulaney doesn't know if the iPhone has a firewall, has no reason to suggest that its installation of OS X wouldn't offer a firewall, and offers no reasons why a mobile device would need a firewall anyway