This article discusses the role of the half-shekel as an atonement for the census taken of Am Yisrael. We also explore the story of the census and its subsequent plague during the time of King David, whereby Chazal say that the plague broke out as a punishment for the people's failure to demand that the Temple be built. Examining this event as well as Haman's decree threatening Israel's annihilation during the time of Achashverosh can shed light on the purpose of the half-shekel as a reminder to God of the silver sockets in the wall of the Temple, therefore providing atonement for their sins. 

Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion