This scam pops up every once and a while. What happens is he pays out the first few times, then eventually when people start sending him larger amounts of funds he doesn't send back. It's happened hundreds of times on BitcoinTalk. Often times they use sockpuppet accounts to pay themselves to make it look like they're really paying out.
If you want to give away money, do not ask people to send you money first or we'll assume your doing this scam.
I agree , left a negative feedback. @OP if you want to do a giveaway simple send to all the users 0.005 / 0.01 btc . Have a great day,
redsn0w