I guess I am going to be a dissenter and say: yes, you should be worried.
The one thing that separates Bitcoin from VISA, Paypal and the Banks is the distributed transaction ledger. Anybody can add to the transaction ledger so long as the expend sufficient resources: termed "proof-of-work". Having mining concentration so concentrated breaks the design assumptions of the protocol.
The first time this happened (with the DeepBit pool) self-regulation worked. This time, the culture appears to have changed. Instead of pulling their hash-power, many hashers are asking for a protocol change to mitigate the problem instead. Various developers have mentioned such emergency coding in the past, lending credence to that argument. However, in my opinion, if that comes pass: The Bitcoin experiment will have been a failure.
How A Mining Monopoly Can Attack BitcoinI also plan to complete selling half my BItcoin by Friday.
I am selling half of my Bitcoin holdings because of GhashTwo reasons:
- I need the money
- I don't believe for a minute that Ghash.io shut-down or redirected any hash-power; other than to solo mining.