When to Tell

You just received some "juicy gossip", "confidential information", "shared opinion" or any other type of information from any source. When is it ok to share it, who is it ok to share it with & when is it not ok to share it?
While you think on this, I will ramble on some more about, I don't know, "random stuff". I have been caught in this trap/situation more times than I care to remember & I would say that for most of the time I get it right but on those occasions when I don't, I screw it up bad.
Your friend tells you that they did something illegal or harmful to somebody else, do you tell anybody?
Your friend tells you some personal information that may jeopardize their standing in the community & perhaps lose friends, trust & their job, do you tell anybody?
You hear from somebody about an incident involving people you know but who arent friends that involves illegal activity or an action which may harm somebody. Do you tell anyone?
Here is one of the grand daddy dilemas that we have all found ourselves in. A friend or family member tells you some juicy gossip about somebody else. Do you say anything?
There are so many more scenarios & examples I could give but don't have the patience to continue my single finger typing, to mention them all nor do I really care to give more examples because I think you have the idea?
I can't say when it is ok to repeat something you hear or observe but what I can say is that when we say it, there is no way to take it back. You may have the best intentions, you may be trying to protect somebody, you may be trying to hurt somebody or you just might be trying to have something to say because your boring life doesn't allow for any substantial conversational information.
Once again, I don't have the answer & I have no advice except what I previously have said, so good luck on making this decision on your own. Just remember that the phrase "Don't Kill The Messenger" wasn't made up, it actually is a reality because you can put yourself in the middle of something you are not part of & even if you think you are helping somebody, you will probably be the one that gets hurt because you started blabbing about things you werent involved with.