Last year I compiled two charts on global ad spending and they ended up getting a lot of attention. The data is broadly available but somehow it is hard to find good charts that summarize well this information. The planet hasn't changed that much from 2013 - the US still dominates the roughly 550 billion dollar global market by size (far ahead of Europe) while growth is in the developing world.
More interesting is the division in terms of the type of advertising. Digital has surged ahead faster than expected and the real division between digital ad types manifests itself in terms of whether the ads are served on a mobile device or on desktops. Last year, people were much more concerned about the contrast between search and social media spending. In this sense, this year will probably mark the big transition to mobile advertising. It is also important to note how well TV is hanging on to its share of advertising budget. Print, as expected, continues to decline (although not as fast as some thought).