Lists are extensible collections of items having an order. Items can be inserted at any point.
Adding items at the front or back has the same cost.
Lists are good for keeping track of groups for use in bulk.
Lists are not good organizing objects by attributes, since searching a list gets slower and slower as a list gets bigger.
There's a special kind of list configuration, memberloc, where the links for the list are stored in the objects of the list. This is useful when it is important to be able get rid of list members quickly.