Here are a few more papers (mostly social science perspective. Sorry I couldn't link to all; they come from a folder of pdfs for my lit review):
Combs, T. (2013). Making meaning of body-size diversity in magazines: A grounded theory analysis of reader comments. UNIVERSITY OF MISSOURI-COLUMBIA. [thesis]
Koteyko, N., Jaspal, R., & Nerlich, B. (2013). > Climate change and ‘climategate’ in online reader comments: a mixed methods study. The Geographical Journal, 179(1), 74-86.
Len-Ríos, M. E., Bhandari, M., & Medvedeva, Y. S. (2014). Deliberation of the Scientific Evidence for Breastfeeding Online Comments as Social Representations. Science Communication, 36(6), 778-801.
Nielsen, C. (2012). Newspaper journalists support online comments. Newspaper Research Journal, 33(1), 86-100.
Çatalbaş Ürper, D., & Çevikel, T. (2016). Editorial Policies, Journalistic Output and Reader Comments: A comparison of mainstream online newspapers in Turkey. Journalism Studies, 17(2), 159-176.
Quinn, K., & M. Powers, R. (2016). Revisiting the concept of ‘sharing’ for digital spaces: an analysis of reader comments to online news. Information, Communication & Society, 19(4), 442-460.
Hlavach, L., & Freivogel, W. H. (2011). Ethical implications of anonymous comments posted to online news stories. Journal of Mass Media Ethics, 26(1), 21-37.
Cenite, M., & Zhang, Y. (2010). Recommendations for hosting audience comments based on discourse ethics. Journal of Mass Media Ethics, 25(4), 293-309.
Regan, Á., Shan, L., McConnon, Á., Marcu, A., Raats, M., Wall, P., & Barnett, J. (2014). Strategies for dismissing dietary risks: Insights from user-generated comments online. Health, risk & society, 16(4), 308-322.
McCluskey, M., & Hmielowski, J. (2012). Opinion expression during social conflict: Comparing online reader comments and letters to the editor. Journalism, 13(3), 303-319.
Slavtcheva-Petkova, V. (2016). “We Are Not Fools” Online News Commentators’ Perceptions of Real and Ideal Journalism. The International Journal of Press/Politics, 21(1), 68-87.
Bergström, A., & Wadbring, I. (2014). Beneficial yet crappy: Journalists and audiences on obstacles and opportunities in reader comments. European Journal of Communication, 0267323114559378.
Winter, S., & Krämer, N. C. (2016). Who’s right: The author or the audience? Effects of user comments and ratings on the perception of online science articles.
Weber, P. (2014). Discussions in the comments section: Factors influencing participation and interactivity in online newspapers’ reader comments. New Media & Society, 16(6), 941-957.
Secko, D. M., Tlalka, S., Dunlop, M., Kingdon, A., & Amend, E. (2011). The unfinished science story: Journalist–audience interactions from the Globe and Mail’s online health and science sections. Journalism, 12(7), 814-831.