MINYANVILLE ORIGINAL Global advertising firm ZenithOptimedia helped kick off the 40th UBS Annual Media and Communications Conference in New York City today by releasing its forecast for global ad growth through 2015. Global ad expenditures are projected to continue their upward growth trend according to the company's research. The expansion in spending will increase year over year from 2.2% in 2011 to 3.3% in 2012 4.1% in 2013 and 5.6% in 2015. These figures represent a notable turnaround from a 9.6% ad spending decline in 2009 the deepest slowdown on record. In total global ad spending is expected to reach ...