He was about to give proof that he was the real Satoshi. He once announced that he will move some of Satoshi's coins (which were mined in 2009 and not moved since). But later he went back on his promise, saying that he risked arrest from law enforcement agencies, if he prove that he was the real Satoshi.
Reality is: He can't, because he doesn't have control over any of Satoshi's keys.
It is quite possible. Some $4 billion worth of Bitcoins are locked up in Satoshi's wallets. I hope that the private keys are lost forever. Else, if someone dumps all that coins in a short period of time, the exchange rates can crash.