This document discusses how librarians can use social media to benefit library users. It provides examples of how libraries are using social media platforms like Twitter and blogs to market services, answer inquiries from users, and collaborate with researchers. The document also discusses how alternative metrics (altmetrics) can help measure the broader impact of research by tracking mentions and shares on social media and other online platforms. Altmetrics provide additional context alongside traditional citations and can recognize dissemination of research through different formats and channels.