1) What ethical expectations are established by the venue?
YouTube guidelines for visiting the site are being followed. The comments are public and viewers do not need to have signed up to YouTube with a personal account to read any of the comments made.
2) Who are the subjects’ posters / authors / creators of the material and/or inter/actions under study?
In order to post comments one has to have a YouTube account and existing comments made have been approved by the account holder of the videos.
The names of the posters are mostly pseudonyms, this includes the uploader of the videos, although the programme was initially made by the BBC and has been split in 7 parts. The programme was uploaded in September 2008.
3) What are the initial ethical expectations/assumptions of the authors/subjects being studied?
You Tube comments are public. Those that are posting comments are aware of this via their initial sign up policy.
More info is available via YouTube support pages
4) What ethically significant risks does the research entail for the subject(s)?
It is unlikely that using examples of any of the comments posted publicly and made available as part of this research would harm the individual who made the original post nor the uploader of the videos.
It is unlikely that comments are made by children. Individuals who explicitly show signs of a mental illness may visit the YouTube site but in view of this concise study it is unlikely there will be any reference nor use of their comments which may make them identifiable.
As the programme is made by the BBC there is a possibility that the BBC will take action to have it barred from viewing due to potential licensing issues.