Over $40B is spent on digital marketing in the US, but a survey on ad blocking reveals that 41% of respondents, aged between 18 and 29, used ad blockers! Ouch, that’s the millennial group advertisers are after!
This NYT article puts it into perspective: http://www.nytimes.com/2014/08/22/business/marketers-are-sizing-up-the-millennials-as-the-new-consumer-model.html?_r=0