Social media has revolutionized the various ways and means of marketing products, services, and communication in different organisations, including libraries, in this era. Today the world is shrinking socially more in virtual environment and it is very easy for people to create, share or exchange information, ideas and others are not limited to the use of day-to-day activities. These activities of pictures and videos among the virtual communities and networks in our libraries. This paper looked at the concepts of social media, social media marketing and social networking in libraries as tools for information-sharing services. The paper also focused on the benefits of using social media in libraries. This paper also pinpoints some social media products and services such as Facebook, blogs, Instagram, micro blogs YouTube, and social news sites. The challenges associated with using social media in libraries were highlighted. Recommendations were drawn on how to enhance social media marketing and social networking in our present-day libraries.