North America accounts for the greatest share of all digital ad spending, at 39% as of the end of 2012. As emerging markets in Asia-Pacific and Latin America up spending, however, North America and second-place Western Europe will lose share slightly throughout the forecast period. By 2016, 36.7% of spending will come from North America, and 23.7% from Western Europe. By the same year, Asia-Pacific will contribute 29.8% of all digital ad spend in the world. Read the rest at eMarketer.