Postgres Contains/Contained By Array Operators

Today I learned about the Postgres 'contains' array operator (@>). This compares two arrays, returning true if the first array contains all of the elements of the second array.

myapp_development=# select array[1,2,3] @> array[1,3];
 ?column?
----------
 t
(1 row)

myapp_development=# select array[1,2,3] @> array[5,9];
 ?column?
----------
 f
(1 row)

It works in reverse via the 'is contained by' array operator (<@).

myapp_development=# select array[1,3] <@ array[1,2,3,4];
 ?column?
----------
 t
(1 row)

A practical example might be comparing two arrays, one of names and one of common nicknames associated with that name.