Gretchen Rubin talks about gossip in The Happiness Project. Basically she vows not to do it and comes up with all these shoulds around it. She doesn't come up with any reasons why it's not good except that if you say something bad about another person, that it gets transferred to you, which in itself is a pretty good reason. But aside from that, I'm unsure if it's bad or good. Let's take The Bachelor. The other night I went over to a friend's house and we talked about it a lot. That's total gossip, but is it bad? I do think it's bad if what you are saying/putting out into the universe is criticism and judgment.
I believe that what Carolyn Myss says is right - that every thought is a prayer. We create our lives with the thoughts we think, so I do believe it's good to focus on the good. With that thinking, it's probably best to talk only about issues that directly relate to someone present, that way you're more constructively trying to work things out. Versus - did you hear so and so's marriage has gone bad? Sometimes if I find myself gossiping in a judging way, I will turn it on myself and ask if I'm ever that way and then - is it a problem?
I also think "gossip," this is how we a) figure out our own morals, b) try to understand each other, c) work out our social/community morals. I think it's sort of unnatural to repress our urge (need?) to talk things out. In my opinion, I think it could be spiritual bypass to not talk big issues out. Now, I get judgment is not all that useful, but if we can talk about these things while examining our judgment we could grow from them.
In short I do think it's bad to talk badly about people without examining yourself. And I think it's best to be circumspect about how you talk about people too since it reflects on you and it's good to consider what you're putting out in the universe.