The value of e-government, services to citizens by public institutions through the internet, is dependent on the mutual adoption of e-government by both the public institution and the citizens. This paper describes a longitudinal study of e-government adoption by municipalities and citizens in Denmark. We studied the e-government initiative Digital Post ¬¬– encrypted digital communication between municipalities and citizens. Over the three-year adoption period, we found four adoption patterns among municipalities, characterized by a slow, late, gradual or early increase in the use of Digital Post. The adoption patterns among citizens were less distinct. We calculated the realized savings to only 20% of the anticipated savings, leading to a deficit of nearly €5 million in 2013. Municipal funding was reduced according to the anticipated savings. In addition, the variation in adoption by municipal staff explained much more of the variation in the deficit than the variation in adoption by citizens did. We wish to draw attention to the overly optimistic expectations of savings from e-government and to a need for further research into the governmental processes of e-government.