We explored the ways the libraries used Twitter and Twitter-like social networking tool, Weibo, e.g.: the functions they usually exploit and the corresponding purposes. Each tool, in fact, has different features and their characteristics. Libraries posted texts, refer to as a 140-characters tweet, and with a hyperlink so that the users could get more information. It involved more than one motive, for instance, announce an event & promote the library collection. Besides, the librarians tended to promote library resources via other actions, like sharing. Precisely because of the simple actions it became possible for libraries to use Twitter as a news-feed center.