The long-running Hallmark Channel show “When Calls the Heart” has developed a dedicated following over the course of its 10 seasons. Members of the fan base call themselves Hearties, and their thriving digital community of around 2 million includes people who befriend and support each other offline. Contributor Faith Salie asks Hearties what “When Calls the Heart” means to them. She also talks with Erin Krakow, the show’s star, and Janet Oke, the author on whose work the series is based.