We have a community with a particular 'tone'. We seem to have a single person with a 'nasty' attitude acting as an 'expert' on everything. We'd really 'like' to have a system for the community to 'unlike' his posts anonymously.

Vote with your silence and ignore the buggar. That'll have more of an effect than any rating system! :>) Real easy to install too!  Do you have an ignore feature? Hugely effective if everyone will do it. He/she will just finally go away after not getting the desired effect. Affectionately known as stewing them in their own juices.

I love it... yes, that is in-fact what some of us are doing. However, there are sufficient 'socially' helping people that he's able to draw in (like me) until the thread 'tone' makes visitors get the wrong impression.

What we'd really like to do is create a system that 'teaches' the poster about their 'tone' - by [#] of 'likes' OR NOT!

I take it I'm creating a 'tool' that isn't commonly needed?

Oh I don't know about that. I'm sure it would come in handy to help in getting the attention of "he/she who knows all" in a very subtle way.  A SMITE button might come in handy too! They get an anonymous message, "I smite thee! So there!"