He said he's giving away 1 BTC on Ripple.   In order to do that, he is giving people an IOU for a BTC (a PROMISE to pay you 1 BTC)  that can be redeemed by you giving him back the IOU.  He knows this, knows he will not redeem any of his IOUs (won't fulfill his PROMISE to pay you the BTC) and is using the trust he is asking people to give him to steal BTC IOU's issued by legitimate providers that will redeem their receipts for real BTC.   It's a scam, he's running the scam and he's a scumbag for doing it.