Just keeping this for record about $broadcast vs $emit in $scope and $rootScope.
Source: StackOverflow
$rootScope.$emit only lets other $rootScope listeners catch it. This is good when you don’t want every $scope to get >it. Mostly a high level communication. Think of it as adults talking to each other in a room so the kids can’t hear them.
$rootScope.$broadcast is a method that lets pretty much everything hear it. This would be the equivalent of parents yelling that dinner is ready so everyone in the house hears it.
$scope.$emit is when you want that $scope and all its parents and $rootScope to hear the event. This is a child whining to their parents at home (but not at a grocery store where other kids can hear).
$scope.$broadcast is for the $scope itself and its children. This is a child whispering to its stuffed animals so their parents can’t hear.
tl;dr (this tl;dr is from [@sp00m][1] answer below)
$emit dispatches an event upwards … $broadcast dispatches an event downwards
[1]: http://stackoverflow.com/a/26752415/699294