Libraries have been providing services to users for many years with little change. The OPAC replaced the card catalogue but the basic service changed very little. The technologies introduced by Web 2.0 are starting to change the way libraries are interacting with their users. Blogs, Wikis, RSS feeds are all examples. This is what we now label Library 2.0. There is something more fundamental occurring than just the use of social networking tools in a library context. The opening up of systems, services, and data will result in new ways to deliver library services to the user. Library systems will be built with components from many sources. Data and services will be shared to proved library services relevant to the user, wherever they are. Open web-centric technology is dramatically reducing the costs and complexity of developing these systems.