The early days of the Internet brought with it some optimistic predictions that it would contribute to achieving the ideal of a democratic society by enabling individuals and groups to express their opinions easily. However, these optimistic predictions began to fade as the virtual world gradually filled with homogeneous groups, where similar voices came together and closed themselves to opposing views. Although the existence of such communities, called echo chambers, dates back to the pre-internet era, it is generally accepted that digital environments such as blogs, forums and social media sites as well as the filters that allow personalization enable users to shut themselves off to different voices in the Internet environment, making it easier for echo chambers to form and maintain their existence. Echo chambers, with their structure that limits the exposure of group members to opponent views and where similar voices are reinforced by repetition, lead to undesirable social effects such as polarization, posing a threat to democracy, facilitating the spread of false information and fake news, and normalizing deviant behaviour. Reducing the harmful effects in terms of social dialogue and cohesion first requires to be aware of such communities. This article, which aims to increase awareness on the subject, tries to draw a framework of echo chambers for stimulating discussions to overcome any shortcoming in it. In this review article, firstly the concept of echo chamber is discussed, then the characteristics of echo chambers, the factors that lead to their emergence and their social effects are tried to be revealed, and finally, some solutions are suggested.