By the end of this year, digital will overtake TV ad spending in the U.S. for the first time. Digital ad spend will reach $72B and TV will grow to $71B. Strategies that worked one year are not guaranteed to yield the same results the next, which means marketers must be on the lookout for change and innovation. So how far did we come in 2016, and what does 2017 have in store for digital marketers?