zip it

Exactly what is gossip?

Merriam Webster says this:1 : a person who habitually reveals personal or sensational facts about others

2 a: rumor or report of an intimate nature b: a chatty talk
I was thinking about this because I was thinking of someone I knew who is in prison and I wondered "does so-and-so know that so-and-so is in prison?"  Then I realized that it would probably be gossip for me to say so.   But, if I tell someone that another someone we know has joined the military and is stationed in Iraq, that doesn't seem so gossipy.  
Is it just the nature of the information?  If it's positive, its ok, but if its negative, its gossip?  Someone had a baby!  Yay!  Someone is getting a divorce.  Shhhh.
Definitely untruths and rumors are gossip.  But what if we know something for a fact?  The dictionary says personal or intimate things.  Well, isn't having a baby rather personal or intimate?  We know that slander, backbiting and deliberately trying to cause hurt are wrong.  Anybody have any more insight on this that I do?
Let me see what the Bible has to say about it. Ok, well.  It doesn't help much with defining it, other than some verses in Proverbs that define it as betraying a confidence.  The Bible certainly comes down hard on it, including it in lists that are full of "terrible" sins. Things we probably wouldn't consider doing.In 1 Timothy it is associated with being a busybody.In the NASB the word malicious is frequently found before the word gossip.  And in Proverbs it says not to even hang out with one.
Ok, so gossip is very bad.  It involves breaking confidence or being a busy body.  But I'm still not sure where that line is?  If it could cause harm then its gossip?  Is that a good guideline? Does anyone have any thoughts?
Notice I'm not even going to touch "chatty talk."