An estimated 96.6 million U.S. adults will be digital coupon users by the end of 2013--and their numbers are expected to top 100 million by 2014, according to a new eMarketer study.

Mobile coupon users are on the rise as well, expected to jump from 31 million in 2012 to 40.8 million in 2013. That number is expected to continue to grow as smartphone penetration widens, with six in 10 U.S. adults will use both digital and mobile coupons by 2015.

Deals and coupons top the list in terms of the type of mobile content users most want to receive from brands, closely followed by free tools (such as shopping lists and reminders), interest-based info (recipes, sports scores), and location-based info (store locations, promotions).

Affluent Americans are especially poised to take advantage of growing digital and mobile coupon offerings, the report explains. Well-equipped with digital devices (a January 2013 Pew Internet and American Life Project survey found that nearly one-third of mobile phone owners are in the $75,000-plus income bracket use their phones to compare prices in-store.)

Though marketers generally extend coupons and digital discounts in an effort to lure new customers to a brand, the majority of shoppers (64 percent) say they typically use coupons to lower the cost of a purchase they would have made anyway.