I have no clue. For now, if you don't want people to see what you're saying to others, you could make an anonymous thread so no one will know it's you. Sorry that I can't really help with this.
Whenever you become a full member. Typically after a few months after joining you can apply for full membership.
You can write on people's walls if there is someone specific you want to talk to, but do bare in mind that the message isn't private and so other people can read it, as someone else said you can make an anonymous thread or you can tell us what's up if you need to talk about something and we can try and help.
