For those tuning in, Bitcoin is undergoing what's known in the investment industry as a "spin-off". That is when a company splits into different companies that are independently managed and holders of the original company get units of each. This is what happened with HP, when it spun off Agilent. The reason for the split is that people mining Bitcoin can not agree on the features that Bitcoin should have.

This causes issues because Bitcoin was never engineered for this contingency. In the ideal case, you would be allowed to select which blockchain you are spending your tokens on. Bitcoin transactions do not contain any information about which blockchain they should be allowed to be spent on, so all transactions spent after the fork are valid on both blockchains regardless of the author's intentions. BCC could have fixed this by provisioning their transactions to be chain-specific, but it seems they did not.

There are significant tax ramifications of this, which are sure to cause a headache for everyone. It seems to me that the tax basis of the original Bitcoins will become diminished by the proportional amount of the value of BCC on the day of the spin-off.