Google disabled 49% more ads in 2015 than the prior year, as the Internet giant developed new ways to detect a rising tide of dubious online marketing tactics. The Alphabet Inc. unit, the world's largest digital-advertising company, said it removed more than 780 million ads in 2015 for violating its policies, up from 524 million in 2014, 350 million in 2013 and 220 million in 2012.