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!