How good are data detectors on Lion? Really good. Check out this example of their integration in Apple Mail:
As in Leopard and Snow Leopard, anything that resembles a date or time is picked up if you hover the cursor over it. But look at the dialog that appears when I accept the offer to add the event to iCal:
The app has read through the entire mail, noted the 2pm, associated it with my chosen date, and combined the two into a calendar appointment. Not bad!