RTB and programmatic are taking over the digital ad industry. It is estimated that 90% of U.S advertising will be bought programmatically by 2017. Programmatic advertising allows publishers to unlock the value of underutilized inventory by optimizing CPMs and targeting. It may be a few years before real-time, cross-channel targeting and optimization become the norm, but forward-thinking media companies are already making rapid progress in this direction and seeing real benefits. Beneath the associated acronyms and buzzwords, the fundamentals of programmatic advertising are straightforward. View the infographic below to understand the four main approaches to programmatic buying.