This document discusses how public libraries can use Tumblr to engage new audiences, especially young adults. It provides tips for getting started with a library Tumblr account, including choosing a theme, describing the library's mission, using consistent branding, and gaining administrative support. The document also offers strategies for using Tumblr for readers' advisory services like book lists, reviews, and discussions. Additionally, it profiles several notable public library Tumblrs and suggests ways libraries can promote local content and events.