Apple has put in place a system that will allow it to deactivate applications that it hasn't approved on an iPhone remotely.
The find comes from Apple hacker Jonathan Zdziarski, author of iPhone Forensics, who has found that there is a remote url that Apple is using to keep a list of the offending applications on devices.
According to Zdziarski, this url appears to keep a list of black listed apps which appears to contain a test application name.
“This suggests that the iPhone calls home once in a while to find out what applications it should turn off. At the moment, no apps have been blacklisted, but by all appearances, this has been added to disable applications that the user has already downloaded and paid for, if Apple so chooses to shut them down.
“I discovered this doing a forensic examination of an iPhone 3G. It appears to be tucked away in a configuration file deep inside CoreLocation.”
So far there is no reported cases of Apple using the system. It is thought that the system has been put in place not to randomly remove applications from your iPhone, but to stop the spread of malicious applications, although as some commentators are citing around the web, "Apple could presumably deauthorize applications already installed on every iPhone" at the press of a button.