It's good to have a bunch of friends - both online and offline... so that if someone is busy/overwhelmed/not interested in our current interests/preoccupations/problems we can find someone else!! Or if the present friends aren't interested, we can find someone new!!
Dean, sorry to hear you had a bad experience with people... not everyone is like that, you know!!
It's good to get to know people well first, and build trust slowly, so that you know who you can trust with what!!
Many people trust to soon (or say too much online or offline, without thinking) - then again, some may trust too late or not at all.. there needs to be a sort of balance I guess, and it's not always easy to find it!!
I hope you did tell the people that you were upset with what they did.. Not sure how old you are, some people especially when young can be reckless or may not regard some things as needing to be 'private'...
Then again, sometimes there can be 'overwhelm' and if the person doesn't know how to help you they may talk to someone else to get info/input.. (and sometimes maybe that other person isn't so reliable, or sometimes they are..) It's good to talk about these things ahead of telling something to a friend or anyone.. What is to be 'private' and what not etc.
And even if you do so, they may blurt it out inadvertently or when upset or something, and without meaning to put you into a bad position.
Think about it also: is it really THAT important??
Sometimes secrets must be kept, sometimes 'secrets' aren't really secrets or that big a deal and input from other people (not just one friend) could even be helpful!!
(I don't know your situation so can't comment on that!!)
If you live in a small town or are still in high school/college, there may be more talk going around too, depending on who you hang out with..
Obviously if you totally DON'T want something to be known to anyone, better keep it private or maybe write in a journal in some code/encrypted or a language no one understands, or talk to a therapists/psychologist or priest who has an ethical codex so that they must keep your details private! Even then some things may get to be known, so hmm.. Maybe it's better to work on a different point of view so that you 'deal' with the situation 'even if other people find out about this, so what?' Many people have probably gone through what you've been going through, we are all just human...
You can have fun with friends even if you don't tell them all your secrets, ya know?