In just the first six months of 2014, digital ad revenue has already increased 15 percent to total $23.1 billion, according to PwC US. This increase is in comparison to the same period in 2013 and shows that mobile revenue is largely responsible for this increase, rising 76 percent in just a year, or $5.3 billion.

A breakdown of mobile revenue shows that mobile search made up $2.7 billion and mobile display $2.5 billion, respectively. Such a large increase in mobile revenue in so short a time shows brands are making large monetary commitments to mobile, as it takes increased precedence in the digital landscape overall.

Social media revenue also saw big increases- 58 percent- rising to $2.9 billion. Search revenue, a big chunk of digital ad revenue, saw an increase of 4 percent, clocking in at $9.1 billion.

Performance-based advertising (65 percent increase) is increasing at a faster rate than impressions-based advertising (34 percent increase).