Internet advertising is about to make another notable achievement. In 2014, U.S. ad spending on the medium will outpace print for the first time, according to a new forecast from ZenithOptimedia, a Publicis Groupe agency based in London. It predicts that online spending will total $42.96 billion this year, up 18.4 percent from $36.29 billion last year. Toni Fitzgerald reports that ZenithOptimedia notes that by 2018, 82 percent of the U.S. population will have smartphones.