When you sign in on the message board, scroll all the way down the page and you can see who might be in the site, or you can do the same by clicking on the list all users on the top of the bar.
To your left of the board is a chat box where you can type in a message, hit send message and you can talk back and forth there.
NOW it may show some one in there BUT they may not be. from the time you sign out it will take your name three mins to disappear. So don't think some one may not want to talk to you, they may be gone.
AS for me, a lot of times I'm in and out, some times I don't sign out, I may leave to go to another window to post something on Face book or Twitter. SO if you send me a message and I don't answer give me a few mins as I may be in another window but coming right back. I try to answer every one and most of the time hollar at everyone I see unless I'm in a hurry running back and forth.
So if you see me in there, give me a hollar, I will answer if it's 30 mins later LOL