I do not believe in talking about someone behind zir back; I consider that very disrespectful. Everything I have written about any problems with any of my friends and everything I will write, I have ALREADY TOLD THEM FIRST and usually discussed it quite thoroughly. (except I can think of one case when I did not. It was a very minor issue (the person thought I was boring and that bothered me), but nonetheless I should have discussed it with zir first.) If I have an issue with someone, I keep it to myself until I discuss it with the primary person. After that, I feel free to discuss it with whomever I want, because it is part of my life and as such the story belongs to me. Usually at that point I have worked out the issue and I include the reconciliation in my telling of the story, but I don't consider the reconciliation necessary.
So if I don't have the guts to approach the primary person about an issue I have with them, I will not discuss it at all, unless and until I have confronted the primary person. If the primary person is not a friend of mine, I do not feel that I owe them the courtesy of telling zir FIRST, but I do believe that I owe them the courtesy of not talking behind zir back.
I think if 'Aye', talks about 'Bee' without telling Bee FIRST, or at least simultaneously, that is extremely disrespectful to Bee and deceitful of Aye. And if Aye talks about Bee behind zir back, without ever telling Bee zir words, that is a sure sign that Aye doesn't believe what ze is saying, and therefore it is most likely untrue.
The one exception is if a friend says 'I need your advice on this, I want to approach so-n-so but am not sure how.' I think when you are coming at it from an angle of intending on talking to the person and working it out, and you're just trying to get advice on HOW to approach it, that is completely different. But it should still be with only a VERY few, very trusted people, and confrontation should definitely happen afterward.
And flipping the coin, if one of my friends talks negatively about another behind zir back, I will mention it to them. I will not say specifics (unless speaking to the two people I have no secrets from (my soulfriends)), but I will say, "so-n-so said something about you, but I do not believe it (and/or) I do not agree with them (and/or) I want to hear your side of the story." I think for me to keep it to myself would be a breach of trust with the person talked about. To listen to someone talk negatively about my friend behind zir back, and do nothing -- that I will not do. (obviously if the person you're talking about is not a close friend of mine, I will not get involved in the matter because that is none of my business) And if this bothers you, go ahead and unfriend me, or if you say negatives about a friend of mine without telling them first, filter me out of it. I apologize for not making this clear earlier, but it's never been an issue until lately.
If the negative-talker doesn't want the person ze's speaking of to know, ze shouldn't make it known. Once knowledge is in my head, it is MY knowledge and MY responsibility as to what to do with it. I can't say, 'well I didn't create this piece of knowledge and therefore it isn't my responsibility.' Knowledge is owned not by the creator but by anyone who knows it. What I know is my responsibility. If I know someone is lying to my friend (and speaking behind someone's back IS a lie of omission) and I do not tell zir, I am also guilty of a lie of omission.