Mining .05BTC per hour for last several hours. Hashrate approx. 300GH/s?
For a brief period they were mining around 2-3THS, maybe an hour, then back to 300.
Those bigger payouts are sent manually probably from the miners they are testing (or from trolls). There will probably be more.
The transaction can be traced to BTCguild if you look at where it comes from originally. However they managed it, they mined that btc.
They always trace back to:
http://blockchain.info/address/14cZMQk89mRYQkDEj8Rn25AnGoBi5H6uerWhich is the btcguild wallet.