Investing in better apps and mobile shopping sites paid off for retailers this year, IBM said Saturday, and digital sales were up 21.5% from last year. IBM does not report total sales figures, but Adobe said Friday evening that Americans were on pace to spend more than $2.7 billion online Friday. Both companies said shoppers filled their virtual shopping carts on their smartphones and tablets more than laptop and desktop computers for the first time ever this year. "US consumers have turned into digital shopping ninjas," Adobe analyst Tamara Gaffney said. Samsung TVs, the iPad Air 2, Xbox, Lego Dimension sets, Star Wars Lego toys and Shopkin Dolls were among the most popular items on Black Friday, Adobe said.