WARNING: DANGER OF SELLING CLASSIC ETHER (ETHC)
What is Ethereum Classic?
Ethereum Classic is a project to keep the original censorship-resistant Ethereum going. We believe in decentralized, censorship-resistant, permissionless blockchains. We believe in the original vision of Ethereum as a world computer you can't shut down, running irreversible smart contracts. We believe in a strong separation of concerns, where system forks are only possible in order to correct actual platform bugs, not to bail out failed contracts and special interests. We believe in censorship-resistant platform that can be actually trusted - by anyone.
from https://github.com/ethereumclassic/README
What is the danger?
If you had Ether (ETH) you probably have some Ether classic (ETHC) now since there was a hard fork of the Ethereum network. But be careful as if you sell your ETHC there is the danger of a REPLAY ATTACK that could steal your ETH.
Don't sell your Ether on the non-fork chain unless you are 100% confident that a replay attack is not possible.
from https://twitter.com/koeppelmann
The initial split is not enough. You have to keep the balance of your separate addresses at 0 on the respective other chain. As soon as it receives a single replayable value transfer all your transfers become replayable up to the total sum of the balance the address has.
from https://github.com/ethereumclassic/README/issues/3
More information on Ethereum Classic
Yes there is a danger, if you move Ether on one chain it will most likely get sent on the other chain too. You have to Split your Ether first. I have explained it in more detail in my post: https://steemit.com/ethereum/@scrawl/what-is-ethereum-classic-and-should-you-care