@Chap:
Besides everything PG said, may I add:
1) For those interested in flying Y, it is not as outrageously expensive. This may be of little interest here, but still of some interest. And of a lot of interest to many DDMS visitors.
2) When used for a OW ex-US, the taxes are not as outrageous either. 12.25k miles + $134USD for a OW JFK/ORD-LHR in Y in June is a decent redemption.