Let me quote the good book on this one.(from the Cisco Building Scalable Cisco Networks book).
"Totallyt stubby Area-This is an area that does not accept external autonomous system (As) router or summary routes from other areas internal to the autonomous system. Instead, if the router needs to send a packet to a network external to the area, it sends it using a default route. Totally stubby areas are Cisco propriatary."
BSCN Cisco press.
Catherine Paquet and