These changes are putting some app developers on hold as they determine whether compliance with new standards is possible. For some companies the new rules will result in a few minor adjustments but for others, pre-existing agreements with other services will make compliance far more difficult.
The new programming rules are partly the result of a substantial shift in Apple’s main source of revenue. Mobile devices are becoming a more significant source of revenue than desktop computing, and there is far more pressure on app developers as a result. While some argue that new standards will promote the development of quality apps, others contend that these changes will ultimately stifle creativity.
Source: http://www.nytimes.com/2010/04/13/technology/companies/13apple.html?hpw