With iOS 6, Apple has officially deprecated the UDID as a valid means for advertisers to track app users. The UDID functioned sort of like a Social Security Number for your iPhone, allowing advertisers and third parties to track your behavior across multiple apps… a troubling privacy concern for many. But UDID tracking also had many beneficial advantages, like allowing developers to troubleshoot crashing apps and the like, which inspired some third-parties when their many companies started releasing their own alternatives to UDID.
Apple wasn’t going to leave advertisers and developers without an alternative to use in their apps, though. New in iOS 6 is two new IDs: IDFA and IDFV. Yes, both IDs still track you, and the IDFA is specifically used by advertisers to collect data on you. But the good news is that this tracking can easily be turned off, and it’s much less invasive than the UDID.
Despite a rather alarmist story by Business Insider about the IDFA, the truth is that the new IDFA is actually a lot better for both advertisers and users than UDID tracking.
For advertisers, one benefit of IDFA is that it acts like a persistent cookie, not a permanent number assigned to a device. Using UDIDs, if a user gave away or sold his iPhone, the UDID went along to the new owner. With the new system, a new IDFA is generated for the device, which leads to more accurate data for advertisers and publishers.
From a user’s perspective, it’s also better. Instead of being tracked invisibly by developers and publishers, you can turn off IDFA tracking. It’s not in an intuitive place (Settings > General > About > Advertising > Limit Ad Tracking) and tracking is on by default, but it’s simple to fix.
Should you turn it off? Even BusinessInsider, which seems pointlessly worried about IDFA, has a hard time concluding IDFA is harmful. “Again, IDFA doesn’t identify you as a person to advertisers. What it does do, however, is provide advertisers with “a really meaningful inference of behavior.”” Whether you want advertisers to infer anything is up to you.