Digital world is transforming wares to soft-wares, business to e-business, brick and mortar companies to online companies. With its exponentially increasing nature the transformation is continuing. One crucial value of any company, which is interrelated with all the sub divisions and operations of the company, can be considered as its reputation. This paper mainly discusses the quantitative face of reputation from the social capital perspective and its transformation by the increasing and irrepressible power of technology. We attempt to answer the question "how to represent the digital reputation of the companies in a digital world?" under the effect of transformation from web 1.0 to web 3.0. As a solution we propose a quantitative methodology for aggregating digital quantities collected from social network sites, company web pages, blogs and wikis and we propose a formulation and indexing method, built on different dimensions of digital world and by the way, the companies can be ranked respectively. As a case study, we focus on the stock market companies in Turkey and their digital reputation and we output a digital reputation index but more importantly we discuss the methodology of creating a digital index for the reputation of companies. Finally we conduct diagnostics on the output index to assess its degree of validity. We believe the research will be a guidance for the research studies in the digital reputation index, since it is one of the first index creation methodology on digital reputation studies and data source has a great variety, volume and velocity as the big data. (C) 2015 The Authors. Published by Elsevier Ltd.