Mobile has played a significant part in digital couponing in 2013—more than 28% of people who own a mobile device redeemed a coupon this year. Nearly 70% of mobile coupon users will access coupons via smartphone. eMarketer has revised our projections for the number of US adult smartphone coupon users upward from our previous forecast to reflect the increase in digital coupon redemption during H1 2013. We expect one one-third of all smartphone users ages 18 and older, or 42.1 million people, to use a coupon obtained via app, mobile internet, mobile barcode or SMS this year. The US adult smartphone coupon user base is up 40.9% this year, following 60.6% growth in 2012. New smartphone users, as well as the growing popularity of new mobile apps, local deals, and the integration of couponing into social networks will help fuel increases. Read the rest at eMarketer.