The problem of building a reputation in the traditional brick-and-mortar world has been known for centuries; we know how to build a good reputation, or more precisely how to help in building a good reputation. Even if we are a target of various half-truths and slanders, we are aware that if they are only spoken words, their durability over time is quickly fleeting. However, written text is different from spoken words; its life durability over time is much longer. In our chapter, we bring the overview of what happens if we must suddenly face the problem of building and maintaining a good reputation in the virtual world of the Internet. Thus, the objective of this chapter is to summarize and present the state of the art in the field of reputation; it consists of the definition of basic terminology and then offers the well-arranged theoretical determination of the problem of reputation in both the traditional brick-and-mortar and virtual world.