eComm and D2C will be acutely impaired by the ATT opt-in mechanic coming to iOS (rumored made mandatory in March). ATT doesnt exclusively impact app advertisers, & in fact may disproportionately damage eComm and D2C. Some thoughts on how those advertisers should prepare (1/X)

2/ In the @MobileDevMemo 2020 mobile advertising predictions post, I posit that D2C ad spend may drop by as much as 50% in Q2 2020. FB revealed in December that app-to-web campaigns will be governed by ATT opt in, severely limiting campaign efficiency

3/ FB had only previously discussed ATT in terms of app campaign relevance. This new revelation likely stemmed from further instructions from Apple following FB's initial guidance

4/ FB affirmed in Dec that app-to-web campaigns will be: conversion event limited, aggregated at campaign level, and limited wrt attribution windows (default: 7-day click). This effectively replicates the privacy treatment of app campaigns on app-to-web campaigns

5/ Adam Lovallo from https://t.co/baV6VrUW7E describes 28-day click / 1-day view the "gold standard" for D2C. Why would FB change the default to 7-day? Because it is aggregating conversions at the campaign level -- universally, with what it is calling Aggregated Event Measurement