For me personally, if I feel uncomfortable in the slightest, if the person's not there, if this would not edify the person I'm talking about, it's gossip. Sometimes I'll slip, and I'll just get right back up and try my best not to do it.
I also find that I need to be careful when sharing prayer requests from other people. Sometimes I do find myself judging. Sometimes I might add in my opinion or speculation about this prayer request. And that's not right. I'm creating gossip.
In response to your response Djness, I know we're two different people, but I find that the easiest way to deal with people here is to keep my guard up all the time. I don't allow myself to open up or share personal/passionate things until after I've observed someone for a long time, to see what they're really about. And since word spreads at the speed of light on cc, I tend to just keep my mouth shut in overpopulated rooms. Better to avoid the drama, for me.