bitcoin is interesting in this regard. no one is 'in control' of bitcoin but anyone can contribute to its production according to a set of rules and it has value. it's the bittorrent of money.
It is possible for an alliance to form between large mining pools, and then what do we have?
I'm no bitcoin expert, so I just googled some random words and found this[1] which claims the 5 largest pools mine 57.5% of all blocks in the past 6 months.
Also, the idea that "anyone can contribute" could do with a few qualifiers: anyone with access to a computer, electricity, and the internet - and all the associated infrastructure required to support running those.
