According to Branch, which analyzes mobile app growth and tracks ad conversions, since Apple’s updated iOS asked users if they wanted to be tracked by apps, only 25 percent have agreed. That response has “been pretty devastating for … the majority of advertisers,” suggests mobile analyst Eric Seufert. Advertisers on social network Facebook have seen a particularly strong impact, according to media buyers who noted that not being able to reliably determine how many sales clients are making means it is challenging to figure out which ads are working. Continue reading Marketers Struggle as Facebook Users Decline to Be Tracked