Energy Information Systems (EIS), which monitor and organize building energy consumption and related trend data over the Internet, have been evolving over the past decade. This technology helps perform key energy management functions such as organizing energy use data, identifying energy consumption anomalies, managing energy costs, and automating demand response strategies. During recent years numerous developers and vendors of EIS have been deploying these products in a highly competitive market. EIS offer various software applications and services for a variety of purposes. Some products are marketed directly to end users while others are made available as part of electric utility programs. We have developed an analytical framework to characterize the main features of these products, which are developed for a variety of utility programs and end-use markets. This paper reviews more than a dozen EIS, for which major features include data acquisition, visualization, and demand response. The purpose of this paper is to evaluate EIS capabilities and limitations, plus examine longer-term opportunities for utilizing such technology to improve building energy efficiency and load management.