Usually, when people tell me a secret, it plays out in these ways.
1) I don't care. I forget about your secret a day later, it doesn't matter then because the people who tell me just wanted to let out some steam.
2) I don't consider your secret that scandalous. Which goes along with 1. No, I don't think telling me about your crush makes me so hot for backstabbing and gossip and secret spilling.
3) I tease them about it. The perfect punchline requires me talking about you're secret, I probably will end up doing it.
4) I refer to the secret teller as "my friend" when I tell the secrets themselves.
+1
I don't consider most secrets to be that big of a deal, even those that are considered scandalous by most people. What a waste of my time. Paperoceans also sums up how I feel here.
I'm guilty of 3) but only if it wasn't explicitly told to me that it was a secret. You have to specifically say that you don't want me to tell it; I'm probly not gonna just know because I wouldn't care if it were my own personal info. If you tell me it's a secret I'll probly be pretty good about keeping it under wraps, especially as I don't get the chance too often.
I do 4) as well. What can I say? Making witty and interesting dialogue is an uncontrollable compulsion.

Plus, I'm a huge fan of everything being out in the open.
But E--Js don't like having their secrets broadcast to other people, whereas E--Ps (generally) don't care nearly as much as other types do. The E--Ps I know tend to broadcast all sorts of crazy 'inside' information about themselves all the time.
For this reason, I think E--Ps tend to share others' personal information more than E--Js do. I don't think it's on purpose, or with mal intent. The E--P privacy filter just isn't turned up as high as it is on other types.
If it happens, it just happens, and I only notice afterwards that the person was uncomfortable with me talking about it.
Also, I don't usually care about anyone knowing anything about me. There are only a select few really strange things I wouldn't want anyone to know, most of which I can't even recall. Sometimes it's just about audience, too.
Introverts tend to gossip more on a personal level (e.g., the phone chain). The introversion really helps them internalize the information and keep a tighter rein on it. I have extroverted friends who seem to be asking questions like, "Oh, gee, did I just say that out loud?" When you operate externally (and that's where you "live" so to speak), the processing and dialogue all happens on that external level; introverts tend to bring everything inside of them or just into very personal 1-on-1 settings before pushing the information all around.
+1
So true. Conversation and dialogue aren't only the way I process things, they
are my thought processes.
I don't think this is type specific behavior. I think that the level of closeness/sincerity between the revealer/listener + the severity of the secret in question that is more of an issue than what type either party is. If one of my freinds comes to me for help, secrets or not, I do whatever I can to get them to a better place if they will meet me halfway or better in the effort...
There you go. I'm actually pretty good at directing the flow of a conversation if I need to so if I know someone doesn't want me to say something I'll direct the conversation away from the subject. I'll even do it if I notice they're uncomfortable about it but haven't said anything to me personally.