The rapid growth of technology has made online tools available for education. The ability to discern the characteristics of these tools and to use them appropriately for educational purposes has become increasingly critical. Weblogs and discussion forums are among those up-and-coming tools that have great potential in supporting learning. They have both common features and differences. They are therefore not to be used in the same way for maximum effectiveness. This article compares the affordances of weblogs and discussion forums by following an EST framework, one composed of three key components--educational, social, and technological. It also discusses the implications that the affordances have on teaching and learning. (Contains 1 figure.)