The “online data leak” becomes even greater because mobile operating systems such as iPhone OS, Android, or Symbian are not technologically mature and are highly vulnerable to attacks. All iPhones, including the latest model 3GS, have been cracked so that an arbitrary code with access to all of the data on the phone can be run as administrator. Address data, e-mails, text messages, and other private documents have been compromised by unavoidable software bugs. Data security is not guaranteed.

The nature and duration of the data access are also problems for users of mobile devices. Whereas stationary or ­semi-mobile computers are usually turned on for only a short time, cell phones are constantly in stand-by mode, and the newer ones are even permanently connected to the Internet. This makes it ­possible for an application to communicate with Internet ­servers at any time, and there is nothing users can do to prevent this explicitly from happening. If they disconnect the ­mobile network connection, they cannot receive any phone calls. Apple exploits this with the so-called “push notification”: even in stand-by mode, the iPhone is automatically fed current data which could interest the user. For example, as soon as a football score is available, the relevant application is notified and the cell phone beeps. Amazon uses this capability in its Kindle e-book reader to control a reader’s library. A case has become public in which various volumes, including, ironically, George Orwell’s surveillance thriller 1984, were deleted from the device without any action by the user.

Conversely, however, the cell phone can also send data to the ­Internet. Following a BlackBerry firmware update by a ­renowned mobile network operator, it became known only by coincidence that the update contained codes for monitoring the user. The microphone could be turned on at any time and the data connection activated, allowing someone to eavesdrop on the user constantly. If GPS data are sent at intervals, the user’s position can be tracked. The company Sense Networks already collects and analyzes the position data of cell phone users, correlates them with other data, and makes them available as movement profiles through the cell phone application Citysense.

Position data and a always-on Internet connection can also be used within the framework of so-called mobile social networks. The iPhone application Hoozat, developed by researchers at the University of Colorado, makes it possible for party guests to obtain data from Facebook profiles about people they do not know who are coincidentally also in attendance, to weigh the data against their own interests, and then to choose the most interesting party guests to introduce themselves to. Whether the interest is reciprocated is another matter all together.