The Electronic Brainstorming System (EBS) is a group support system (GSS) tool considered particularly productive in supporting idea generation. Unfortunately, as computer-supported groups are confronted with larger numbers of ideas and supporting comments to organize and evaluate, they may experience information overload. This study explores the problem of information overload within the context of an idea-organization task in a face-to-face electronic meeting. Integrative Complexity Theory provides the primary theoretical foundation, and an Information Overload Model for GSS is introduced. Results from a laboratory experiment provide support for the idea that effective GSS tools can be designed based on a theoretical understanding of information processing, in particular, how information is processed under conditions of high information load. Use of a GSS tool designed to regulate the flow of information, called an Idea Regulator, led subjects to organize ideas with higher levels of complexity, but they also reported higher levels of mental workload. This research suggests that particular attention to the problem of information overload, and research focused on finding theory-based solutions, can lead to more effective meetings.