Block uses several content variables. Only one is permanent.

Name: Block_List
 Tag: BLOCK_BLOCK_LIST
----------------------
Unpinned blocks appear here.


Name: block_n
 Tag: BLOCK_BLOCK_n
----------------------
"n" is the id number of the block. You could plan for BLOCK_BLOCK_1,
BLOCK_BLOCK_2, but it is just easier to let them fall into the DEFAULT
tag and let them get sorted out by the admin.

