Step one: blow up the silo! - Open bibliographic data, the first step towards Linked Open Data

More and more libraries starting semantic web projects. The question about the license of the data is not discussed or the discussion is deferred to the end of project. in this paper is discussed why the question of the license is so important in context of the semantic web that is should be one of the first aspects in a semantic web project. Also it will be shown why a public domain weaver is the only solution that fulfill the the special requirements of the semantic web and that guaranties the reuseablitly of semantic library data for a sustainability of the projects.