Tuning out of eMail conversations

I'm practising inbox zero for a while now. Doing that I realised a few very bad eMail habits getting in my way: mixing To: and CC: and Reply all. So what's wrong:

• To and CC have very clear intentions. Recipients are in the To field, because the sender expects a reaction: a reply or an action taken. CC (originally Carbon Ccopy, now more used as "Just in Case Copy") addresses recipients who should know about the content, but no reply or action is expected (still one is free to reply or act). I frequently see these principles violated. Senders are coming back to me asking "Why didn't you reply" while I was only in CC or I find my name in the To field and there is nothing to be done by me. I'm very tempted to start to ignore mis-labelled messages
• CC lists get longer and longer. Once you have been added to an email conversation is is almost impossible to get off it. Reply to All is too pervasive (and I'm partly guilty there too). The proponents argue, that once taken of such a conversation it is very hard to get back on and information gets lost to the individuals (that's why IBM Connections Activities makes so much more sense - also available in a LotusLive Activities flavour)

In Activities there is a possibility to "tune out" of an activity. You are still a member but it doesn't show up on your dashboard. Even if your are tuned out, new action items will show up in your ToDo list, so information doesn't get lost. I'm very tempted to add such a feature to my Notes client. A view, a form, some script would do:

How much actionable items would I miss then?