You wouldn’t know it from Tripadvisor, but the small coastal town of Newburyport, Massachusetts holds a unique attraction drawing thousands of visitors—in the last two years they’ve hailed from 41 U.S. states and 22 countries. No municipal signs direct travelers to the site, nor is it listed with the local Chamber of Commerce. Tourist revenues flowing to the city of Newburyport notwithstanding, one historical society officer groused that she is sick of hearing about the man whose reputation draws pilgrims from around the world. In Newburyport lies the tomb of the Reverend George Whitefield (1714-1770). Whitefield, the most legendary evangelist in…