Though the entire open letter is worth reading, the juicy bits includes Jobs' main reasons for disallowing Flash on the iPhone, iPod, and iPad platforms:
- The concept of 'Open'. Specifically, though Flash is widely used, Adobe controls the entire Flash ecosystem, which makes it 100% proprietary and therefore entirely closed.
- The concept of 'The Full Web'. Adobe has been bashing the iPhone OS for its lack of providing the "full web" experience due to its lack of Flash support. Jobs notes that nearly all the major sources for Flash-based video provide the open Web standard H.264 encoded versions of those same videos that work great on the iPhone OS platform.
- Reliability, performance, and security. With Adobe's Flash being ranked as having one of the worst security records in 2009 and the noticeable lack of performance on low power devices (like iPhones, iPods, and iPads), the already shaky reliability of Flash in Apple's experience gains no points. Not to mention, have you seen a mobile device running Flash yet? Neither have I.
- Battery life. See the above issues with performance. Flash is a battery killer, especially on mobile devices.
- Touch. Apple's mobile strategy is based almost entirely on a touch interface. Flash, on the other hand, was built to be used by a mouse, utilizing concepts like rollovers which do not exist on touch interfaces.