Recent data collected by Flurry Analytics shows only 4% of U.S. mobile device users are opting in under Apple's App Tracking Transparency framework, Mashable reports. The average daily opt-in rate worldwide is 12%. Flurry tracked opt-in rates from 2.5 million devices since ATT took effect in April. IAPP Associate Editor Ryan Chiavetta, CIPP/US, wrote about advertising technology's reaction to Apple's privacy changes for The Privacy Advisor.