I made a post about Googles Voice Search App a few days ago. This time, Google admitted breaking the official rules of Apple’s iPhone software development kit when it created the Voice Search App.

A Google spokesman said that Google Mobile uses undocumented APIs (application programming interfaces) in order to use the iPhone’s proximity sensor to prompt a verbal search. Apple only allowed iPhone developers to use the APIs that Apple published in its SDK when they create their applications under the terms of that agreement.

The problem with using undocumented APIs is that your application code could break in the future as Apple updates its software, but it appears that a lot of developers appears ready to take that risk in order to deliver a cool feature like Google’s verbal search prompt. [Cnet]