A lot has been written and discussed about the power and benefits of semantic technology. But still when it comes down to quantifying the benefits of semantic technology, you will find very few case studies where it is measured or some kind of ROI analysis has been done. It is always good to know about this case study by Telefonica which is one of the largest fixed-line and mobile telecommunications companies in the world: third largest in terms of number of customers only behind China Mobile and Vodafone, and in the top five in market value. They used semantic technology for their tariff calculation which is a very complex acitivity for an operator of their size. They could achieve 80% reduction in working hours and 75% reduction in errors for activities related with tariff calculation. If Semantic Technology has to become mainstream in the enterprises then we will continue to need more case studies like this.