Find the cache signature for the block.
Build a bookmarks menu for the current member.
Takes some comcode, and return an XHTML menu created from it.
Build menu based off of site tree branch.
Take a stored menu identifier, and return an XHTML menu created from it.
Build a menu branch map from a database row.
Build a pseudo 'stored menu' out of do_next_menus hooks (we create database rows so we can render it as a normal stored menu).