What is the impact if my iPhone has been jailbroken?

A jailbroken iPhone is an iPhone which has been modified to allow the user to install applications which are not released through Apple's App Store. If your iPhone has been jailbroken, you will observe the following behaviour: * Photo slide shows or videos will not be shown on the TV screen although it has been activated on the iPhone at simple mode * In the iPod extended mode, when the user select video or movies, they are not able to scroll down Note: There could be other abnormal behavior with the iPhone function