Over the past decade, a new form of computer technology called group support systems (GSS) has emerged. With GSS, group members communicate by exchanging typed messages instead of, or in addition to, speaking verbally. GSS have proven useful in improving group performance, particularly for creativity tasks such as idea generation. Virtually all GSS tools enable participants to exchange ideas and comments, and some provide special purpose tools to support what has come to be called electronic brainstorming (EBS). This chapter integrates research on EBS and draws conclusions about the effects of EBS. It begins by examining the important theoretical underpinnings of EBS and then examines each of the important ways in which EBS may change traditional approaches to creativity. The chapter concludes with an examination of the effects of group size on performance, because group size is one of the dominant factors in the successful — and less successful — use of EBS.