Members on wall help!

Is there a way to have members show up on the wall page, when they come online? Example of what I am trying to do is that when a member logs in to my site, I would like for them to show up on my wall when I am or any member is posting on their wall. Example: Facebook has that when a member is online. If that will help with what I am wanting to do? Thanks to anyone for any help with this.