According to chemist (the site admin) you have to post more to attain certain privileges. This is due to spam problems on this site. For example as a greenhorn/newbie/cheechakoo you're not able to set up your own avatar. If I remember correctly the setting "Edit your avatar" is there but you can't upload your own. This changes, however, after a certain number of minimum posts (around 17 I think). If you want to know for sure you should contact chemist. Post more + you will be able to send + receive private messages here. I haven't posted this much but private messages are active in my case. So the treshold to reach may be the same as with avatars.