You can specify variables in a BEML player template that can be bound to a value set in the player's publishing code. For instance, you can use a label in the player template like this:
<Label text="{player.parameters.playerTitle}" />
Then you can set a value for this variable using a configuration parameter in the JavaScript publishing code like this:
<param name="playerTitle" value="My Player" />
Or in ActionScript publishing code like this:
config["playerTitle"] = "My Player";
You can also retrieve the value using the Player API:
getModule(APIModules.EXPERIENCE).getPlayerParameter("playerTitle");