Data protection and bulletin boards

John Breslin of (amongst other things) Boards.ie has an interesting post on a data protection complaint from a banned user. The complaint? After the banning, all the posts he had previously made appeared with the word "Banned" next to them (which is the default setting for many forum software packages). The view of the Data Protection Commissioner was that this was an unauthorised disclosure of personal information (i.e. the user's status on the site), apparently on the basis that the username was very close to his real name:

Quite apart from the narrow data protection aspect of this particular case, it raises an interesting issue about the social dynamics of social software and whether the law might hinder effective moderation.

One of the way in which moderators on forums discourage certain behaviour is by putting users into a sin bin or banning them. Going one step further by naming and shaming - i.e. publicising the sanction by labeling posts from those users - has a social effect in two ways. At a general level it may help to reinforce the norms of the site by publicly reinforcing the message that certain types of behaviour are unacceptable and at the individual level it may also act as a deterrent to the user who knows that any sanction against them will be publicised.

If this sounds familiar it's because this argument mirrors, on a much smaller scale, the role of publicity in the criminal justice system. It also mirrors the increasing tendency in other areas for public bodies to "name and shame", whether it be young offenders in England or the list of tax defaulters in Ireland who settle with the Revenue.

The broader issue this raises is whether naming and shaming is an acceptable option - and if acceptable in (e.g.) the context of tax defaulters, why not in the context of troublesome users? Should it matter whether it's a public or private body naming and shaming? Should it matter that the gravity of the "offence" is much greater in one case than the other? If bulletin boards / forums can't publicly reveal which users have been banned or sin-binned, will this make the life of moderators more difficult?