The most impressive growth was seen in mobile, which continued to grab click share from desktop. Smartphone clicks in Q4 2013 increased 1,589% over Q4 2012, and those on tablets rose 335.7%. Overall, mobile grew its click share nearly six times year over year, from 4.2% to 24.3%. A main driver of this growth was the release of mobile-optimized PLAs in October 2013. Read the rest at eMarketer.