Various sources describe Wikipedia's popularity in different ways, including by count of its users, frequency of use, and its utility as an information resource in many fields of knowledge. The Wikimedia Foundation has claimed that Wikipedia has reached billions of readers; commercial web traffic services have ranked Wikipedia as a top-10 website by popularity; and researchers analyzing demographic surveys and user behavior metrics have described Wikipedia readers in enough detail to identify general trends. Researchers note that Wikipedia traffic data is public for examination, and also that the Wikipedia volunteer editorial community invites transparency by developing ethical guidelines to encourage analysis of Wikipedia's impact. Although Wikipedia is popular and its audience metrics are accessible, Wikipedia is unlike comparable media platforms and services in that it is rarely the target of professional, expert, or sponsored content development. We review the literature describing Wikipedia, and offer commentary on the dual nature of Wikipedia as simultaneously a popular communication channel and a media outlet with little documented recognition.