http://sks.pkqs.net/pks/lookup?op=vindex&fingerprint=on&sear...
(ignore the signature from today, anyone could have done that in the brouhaha following today's disclosures)
Based on that, it looks pretty clear to me that Dorian Nakamoto decided to "latch on" to the Satoshi Nakamoto founder's myth, either as a way to boost his reputation/ego or as some practical joke (or both!).
That or Satoshi the Founder is trolling us all.
1. Originally noted a few moments ago by mpfrank on bitcointalk.
EDIT: Duh, it's fake. Obviously, it's possible to set your system clock back. I was so intrigued I wasn't thinking clearly, even after I pointed this very "attack" out during the Ed Snowden GPG affair. Sorry folks, maybe if it were timestamped in the blockchain.