Over the years, Duolingo has become one of the most popular ways to learn a new language. It shook up the market using a free model with gamification, no ads, and a focus on high-frequency words to ...

Like many 7- and 8-year-old girls online, Emily and Kayla Strickland are regulars to Barbie.com and the virtual world Webkinz. But much to their mom's delight, the sisters also have been longtime fans ...