This feature allows event editors to limit the size of the wait list for an event. So if you have an event where you know that a lot more people will be signing up than you have room for, and you don’t want to give false hope to those really far down on the wait list, this is the enhancement for you.
To specify a wait list limit, there is a drop down that will appear when you check “Create wait list when fully booked”. The default is blank (no limit). Once the wait list fills, the sign up button text on the calendar views will change from “Wait list” to “Event is Full” by default.