Salut Gabin !
Welcome aboard and have fun on EF. I've been around for some time now and I've enjoyed this site very much so far. If you are a big fan of chatting, you may check out the sister site called TheChatPage.com.
Now as far as sharing your msn address, the way it usually goes is that you post all your details (where you live, how people can reach you either by email or messenger) in your profile so that it's accessible to everybody and anytime.
Take care and hope to see you around. A +.
Waïti.