If you want to change your current policies on accepting anonymous comments, fine. But when you promise a user that the comment they are about to submit is anonymous, that promise should mean something. Forever, not just until your next TOS change. You shouldn’t have even stored information about who made a comment if they asked you to keep that comment anonymous.
People trusted you and believed in you, and they acted according to their trust and belief. They didn’t know that anonymous really meant “tracked, stored, and correlated, but hidden only until we decide otherwise”.
Those of you out there who think anonymous comments are only about making nasty retorts or spamming- think again. Sometimes, anonymity enables people to talk about their health, their relationships, their issues, their innermost thoughts, things they would otherwise be afraid to reveal. Sometimes, anonymity enables an intimacy that can be a lifeline in rough seas. Anonymous comments can be as deeply personal as any church confession – imagine if your confessions were taped, played to the world, and associated to you forever more.
I suppose the only moral of this story is to assume the worst about any technology that makes promises around secrecy. Perhaps this will encourage pseudonymity – at least then you’re known to be tracked, but you can control what correlation might exist to your real name. If nothing else, this should call into question the practices of any service that supplies that little “post as anonymous” checkbox.