This qualitative case study examined Twitter use by undergraduate and graduate students in three classes. Previous studies have shown that while some faculty use Twitter, few are incorporating it into classes despite many recommendations for such use. This study examined how students perceived Twitter as a classroom tool. As an optional activity, many started with Twitter but fewer continued through the semester. The study reports on content and counts of tweets as well as student self-reports on usage and interest. The researchers found students enjoyed being consumers of tweets but seldom retweeted or replied. Incorporating Twitter in courses will require careful consideration of scaffolding, modeling, privacy and course design. Questions remain as to whether the informal social focus of Twitter may overwhelm attempts to use it in more structured educational settings.