Clicking the icon will print your current zone and location to chat with a More Info chat popup link.
The popup will list your current target's name and HP. If you have nametags enabled it will count the players in the area and list that information so other players know how full the zone is. It will also detect if you have AutoMU installed and put that information in the popup window.
The popup window will also include a link that other players with ShoutOut! installed can click to meetup on you. If they are not on your friends list it will add them, meetup and remove them.