Libraries should offer their patrons web sites which establish the unmistakeable concept (public) of library, the concept that cannot be mistaken for other information brokers and services available on the Internet, but inside this framework of the concept of library, would show a diversity which directs patrons to other (public) libraries. This can be achieved by reliability, quality of information and services, and safety of usage.Achieving this, patrons regard library web sites as important reference sources deserving continuous usage for obtaining relevant information. Libraries excuse investment in the development and sustainance of their web sites by the number of visits and by patron satisfaction. The presented research, made on a sample of Slovene public libraries’web sites, determines how the libraries establish their purpose and role, as well as the given professional recommendations in web site design.The results uncover the striving of libraries for the modernisation of their functions,major attention is directed to the presentation of classic libraries and their activities,lesser to the expansion of available contents and electronic sources. Pointing to their diversity is significant since it is not a result of patrons’ needs, but more the consequence of improvisation, too little attention to selection, availability, organisation and formation of different kind of information and services on the web sites. Based on the analysis of a common concept of the public library web site, certain activities for improving the existing state of affairs are presented in the paper.