It seems with the delay of Leopard Apple is taking advantage of that time by making Tiger a little better. In an update we have not seen for sometime now Apple is preparing to push out 10.4.10. Of course there is no reason why they cannot have a .10, it just seems natural to stop at 10.4.9 before moving to 10.5. Of course if they want to make improvements than its more then welcome. No specific features or improvements are yet to be know for 10.4.10.