Some data collected anonymously from users of an iOS application freely available on the App Store suggests that a good amount of people don't bother picking secure passcodes for their mobile devices. The most common passcode was, not surprisingly, 1234.
The next four common passcodes are just as uncreative: the bottommost button four times (0000), down the middle row of buttons (2580), the top left button four times (1111), and the middle button four times (5555).
This data was collected by Daniel Amatay, an iOS developer, who published the findings on his blog (via TheNextWeb). Amatay collected the data via his application, Big Brother Camera Security, which photographs people trying to guess the user's passcode via a fake iOS lock screen. In the most recent update to his application, he added in anonymous tracking of what passcodes are actually used by users. One may assume that users would generally use the same passcode as the real iOS passcode - which has to be disabled for this application to function correctly (a demonstration is available here).
Another interesting tidbit gathered from the data was the potential use of one's birthyear as the passcode. The below graph suggests a good chunk of iOS users are born between 1990 and 1999, with the 1980 to 1989 group coming right behind. This is assuming that there is not an alarming amount of children under 11 years old running around with iPhones or iPod touches with free reign to access the App Store.
This data stresses the importance of picking a secure combination of numbers as passcodes - or barring that, a password. Then again, passwords are not much of an improvement if people are mashing in 'qwerty' or '123456' as their passwords.
Image Credit: Amitay.us