It has been announced(something which does not normally happen) that Lost is officially ending in 2010, and the next three seasons are only going to be 16 episodes long. Apparently last seasons finale episode flashes of Kate and Jack off the island were flash forwards and these will be included in the next three seasons. That is why they have announced when the show will end, so that people don't become disillusioned by seeing them off the island.Although the writers say the ending will not be as expected.