Abstract: In this article, the author reviewed literature on Web 2.0 in Nigerian university libraries. Web 2.0 is not just commendable, it is necessary and for to service patrons without it in this century is to be left behind in information provision. Library users presently are increasingly becoming technologically inclined. They expect local services to be virtually presented and want information at their beck and call for their individual fulfillment. Web 2.0 is a necessity for librarians because it offers feedback and comment opportunities that allow them to feel engaged with patrons and other colleagues professionally. It is an inexpensive and effective way of interacting with patrons that has never been possible before. Web 2.0 is much more than a mirage, it is real. It is a new and an innovative attitude, a total values system and offers new ways of doing library work. The various manifestations of web 2.0 such as Blogs, Instant Messaging (IM), Flickr, Wikis and Really Simple Syndication (RSS) and challenges to deployment in university libraries were discussed. Deploying Web 2.0 could be frightening but it is necessary that as information professionals, librarians should know the potentials of Web 2.0 if we are to be relevant and ably harness our users’ astuteness.