From the Plug-In’s Description:
Commenter Ignore Button (CIB) lets a user put one or more commenters “on ignore.” To have such an option enabled is a frequent request at blogs and other sites where comment threads are plagued by trolls or other problematic commenters, but where site operators prefer to err on the side of open discussion – or don’t want to get involved unless they really have to. Once users become generally aware of the option, people just seeking attention may either be more polite or move somewhere else, while regular commenters – and lurkers – may become more willing to engage.
You can download it from the Repo using the link above, or you can get it here.
