I used to when I went through that depression-phase. It really helped me get my thoughts in order. Now I don't really need to- I don't feel down that much anymore, I don't have time to write freely seeing that I am always designing/ doing something creative.
I was always open with my stuff too. I remember when i wrote bad things about people, I would tell them right to their face, because that is how I am. For the most part they were shocked that I told them how much I disliked them/ what they do/ did to me, and its funny- despite that, they continued to talk to me and respected me more. Not like I talk to them really... I remember one kid stole my artwork and never got caught, so I basically told him flat out how he is a liar, cheater, doesn't belong in design, etc... Don't really know what ever happened to him.
anyone is allowed to see mine. it's a visual journal so made of scraps and doodles. most of the images have a personal meaning to me that no one can read all that much into. more than anything, it's just kinda pretty.
I wouldn't go out of my way to show them but if they came across it I wouldn't be all that bothered.
I don't, but I'm thinking I should do, not an every day thing, but just to write down what I feel and what's going on, so then later when I want to look back and work out what was going through my mind back then, I can! As now, I wish I knew what I was feeling about someone when I was at uni, and now I have no idea >.<