It's lime juice.  It tastes like the juice of limes.  Many, many limes.  One squeeze (of the bottle) into your clear lemon-flavored carbonated soda will result in a fantastic limeade without all the work of trying to get juice out of a freshly cut lime.  Add some red berries or cherries and you will have a refreshing cool beverage for the upcoming warm weather days.  The decision to add some spirits for a hard limeade is up to you-- and maybe Mike.