Now a much larger study out of the Technical University of Vienna has reached the same conclusion. For that study, researchers examined more than 1,400 iPhone apps and found that more than half of them collected users' device IDs -- 40-digit unique numbers that identify individual phones, according to MIT's Technnology Review. What's more, 36 of the apps accessed the phone's location while five gleaned information about the users' contacts.
Unlike the case with cookie-based online ad targeting -- where users can set their browsers to reject cookies (or click on opt-out links when they're provided) -- people don't appear to have any good way of downloading apps but blocking them from transmitting iPhones' unique serial numbers.
The research could put additional pressure on Apple to either change the design of the iPhone or its approval process for app developers. The company is already facing two potential class-action lawsuits by iPhone and iPad users who allege that the transmission of their devices' unique identifiers violates federal wiretap and computer fraud laws.