Before she released her debut album in 2011, Christina Grimmie entertained fans via the Internet, where she became one of the highest viewed musicians on YouTube thanks to her scaled-down performances of contemporary pop hits. She launched her YouTube page in 2009 and began covering songs by Adele, Miley Cyrus, and Selena Gomez, accompanying herself on piano and earning a large digital audience in the process. One of her viewers was Selena Gomez’s father, who eventually became her manager....