University library users prefer the internet to OPAC, when they search for information. It is necessary to develop interface of OPAC that is nearly as convenient as the internet. This study provides users with University Library Toolbar which is one of the ways to implement Web 2.0, and proved that OPAC is also a convenient and useful searching tool by offering the toolbar. In addition, the causes of the preferences of the internet sites surveyed for this study and the point shown in the comparison between the internet and OPAC are going to be essential materials to implement more convenient OPAC and Library 2.0.