The whole consumer surplus in period 1 is the sum of the dark and light grey areas. This approach has been utilized by Crandall and Jackson (2003) to estimate the US consumer surplus derived from new services like shopping, entertainment and telemedicine enabled by broadband infrastructure. Similarly, Lee and Lee (2006) relied on regression techniques to estimate the consumer surplus for the Korean telecommunications market. In their analysis for the period between 1999 and 2006, the authors determined that in 2006 the consumer surplus generated by broadband represented USD 7.5 billion (or 27 per cent of the total USD 28 billion in broadband surplus). This was calculated on the basis of what users would be willing to pay to adopt broadband and substitute narrowband access. Consumer surplus can also be conceptualized in terms of the benefits that broadband represents to the end user.