as we all know that bitcoin was designed to be a decentralized currency. Yet people have pointed out that 50%+ computing power is owned by only few mining pools. It really hits me hard when people still claim bitcoin as a decentralized currency, especially after yesterday's unfortunate Mtgox incident. Yes, Mtgox surely did a bad coding job. But please really think about who were the attackers?

In order for such faked transactions getting included in the blockchain fast enough and "lucky" enough, I assume it must have something to do with those "centralized" groups of people, at least.