PITTSBURGH—Sherry Yadlosky, a staff member at the Carnegie Library in this city’s Oakland district, answered the phone in her cubicle late in the afternoon of Nov. 1. A woman wanted to know who would be pitching for the Dodgers that night in the final game of the World Series.

Ms. Yadlosky consulted a sports website. “It looks like they’re going to be starting Yu Darvish,” she said. The caller asked whether Mr. Darvish was a good pitcher. Ms. Yadlosky thought about it for a moment, then said: “It depends on your definition...