Abstract
YouTube's recommendation system algorithms have been the subject of controversy and debate, as there have been incidents of the recommendation system offering hazardous, most often extremist content to users. The purpose of this study is to test the hypothesis that YouTube recommendations can contain and promote radical content. The scientific and practical significance of this work is that YouTube has a huge popularity, and knowledge about the algorithms of its recommendation system would help to improve information literacy of users and thus prevent the potential danger that can be caused by exposure to malicious information. This study seeks to popularize the idea that all information on the Internet requires a thorough verification. Improving information literacy of users, this research contributes globally to the prevention of terrorist attacks, acts of self-mutilation, suicide, pedophilia, etc. The sources for the present investigation with description at least one type of radical content were published in the last 5 years. The material of interest was searched through authoritative scientific and metric databases, namely: Google Scholar, Scopus, Web of Science, and PubMed by extracting suitable records. A total of 22 studies were pooled according to the eligibility and exclusion criteria, and a meta-analysis was performed which found that in 13 of them YouTube recommendations contained and promoted hazardous content, in 7 studies the scientists presented ambiguous results, and only in 2 studies the authors found that the recommendations did not contain or promote any radical content. Thus, according to the results of this research, it was found that YouTube recommendations can contain and disseminate prohibited hazardous content, and therefore the authors strongly recommend making adjustments to the algorithms of the recommendations in order to protect users from prohibited information, including the promotion of extremism and violence. Keywords: YouTube, recommendations, recommendation system, hazardous content, pseudoscientific content, radical content, extremism, pedophilia, meta-analysis.