WHAT: a person who helps the congregation turn their focus to God in preparation for His word and sacrament. This can be done through the delivery of a concise message and through leading the congregation in song. The worship leader can also help aid in the flow of the service through the announcement of hymns.
This way, ministers don’t need to worry about who is singing when. When the congregation sings, the worship leader announces the hymn. When the choir sings or there’s a solo/small group, this happens organically.
WHERE: the divine service experience and worship evenings/events
WHO: people who can speak well publicly and who have spiritual depth and enough musical knowledge to lead the congregation in song (the person who teaches a new song must have even more musical knowledge). Note that it’s not required that worship leaders lead the congregation in song – this is just an added bonus.