There's one friend that i've shared everything with, we don't talk much nowadays but I still could tell her anything and know she wouldn't judge. But she's the only friend i'd share everything with, i'm quite closed with others. I share everything with my Mum and Sister too because they're like my best friends.
I don't really know what type of thing you're talking about though Ashley
If it's something you want to keep to yourself (for whatever reason) there's no reason for you to tell your friends.