The paper deals with the creation and design of high quality web sites. Emphasis is placed on elements of information architecture, but also on specific quality attributes of web sites, including accessibility, findability, usability and credibility. Here is presented the methodology of user testing, its implementation and evaluation. Through the testers, the key issues of Study and Scientific Library in Hradec Kralove's web site were identified. On the basis of the findings, suggestions are made to improve and resolve problematic areas of the web site. The text refers to the diploma thesis defended at the Silesian University in Opava in 2017.