What's the difference between the OSPF "default-information-originate" command and the "default-information-originate always" command ?

To Remove Confusion: Using default-information originate will advertise a default route, if there is one in the routing table. By adding the 'always' the default will be advertised even if there is no default route in the table. Consider a router with a default route received from its upstream. It is also using default-information originate downstream to the next router. If, for some reason, that default route is removed from the table, the router will stop advertising the default to its downstream, unless you use the 'always' parameter.