YouTube is one of the world’s most popular web sites and hosts numerous amateur and professional videos. Comments on these videos may be researched to give insights into audience reactions to important issues or particular videos. Yet little is known about YouTube discussions in general: how frequent they are, who typically participates and the role of sentiment. This article fills this gap through an analysis of large samples of text comments on YouTube videos. The results identify patterns and give some benchmarks against which future YouTube research into individual videos can be compared. For instance, the typical YouTube comment was mildly positive, was posted by a 29 year old male, and contained 58 characters. About 23.4 % of comments in the complete comment sets were replies to previous comments. There was no typical density of discussion on YouTube videos in the sense of the proportion of replies to other comments: videos with few replies and with many replies were both common. The YouTube audience engaged with each other disproportionately when making negative comments, however; positive comments elicited few replies. The biggest trigger of discussion seemed to be religion, whereas the videos attracting the least discussion were predominantly from the Music, Comedy and How to & Style categories. This suggests different audience uses for YouTube: from passive entertainment to active debating.

Abstract—Web 2.0 has reshaped the way people interact with Web sites. People are now able to view content created by other users as well as publish their own content on Web 2.0 sites, instead of downloading content created by a single author. Understanding the characteristics of the Web 2.0 sites has become a subject of immense interest to the Internet service providers, content makers and on-line advertisers. This understanding is also important for the sustainable development of the content distribution systems. As an approach to comprehend the characteristics of Web 2.0, significant amount of research has been done in investigating the characteristics of YouTube, the most popular web 2.0 site. In this paper, the characteristics of YouTube, based on earlier works, are studied from both video and user perspectives along with some open research issues. This kind of study is instrumental to understand the driving aspects of YouTube and other similar user generated content (UGC) sites. Keywords-YouTube videos; YouTube users; Web 2.0; User generated content