In this paper we examine the possibilities for analyzing the behavior of library users. We point out that the softwares that we can use cannot fulfill library requirements. There are many data given for on-line searches in library systems hidden from the analyzers. After examining the possibilities and some log files produced by the library systems, we propose how log files could give more usable information for the semantic design of the intelligent library in the VirCA virtual collaboration system and of other on-line systems, too. These data can be applied as input information for intelligent systems in learning user searching behavior and help them predict user needs more precisely.