Hi everyone, this is a quick and dirty explanation in lamens terms for what would happen if you have bitcoin, and the bitcoin chain hard forks in the near future.
What will happen on most exchanges, including Poloniex, BitFinex, and many others (but perhaps not on LocalBitcoins and sites like that), is this:
When/If a hard-fork occurs, Bitcoin will remain, and a new derivative of the Bitcoin network will come into existence as well. Almost all major exchanges say they will not remove Bitcoin (BTC) from their markets, but it will exist as it is and a new "coin", Bitcoin Unlimited (BTU) would be added. All people holding bitcoin, will then have the exact same amount of Bitcoin and a mirrored amount of BTU will be created from the new network.
This means if you have 10 Bitcoins today, and a hard fork occurs, you will also be holding 10BTU as of the point of the hard fork. This is likely why Bitcoin price is moving up still, because people would like to get their share of any BTU that is generated during the hardfork for themselves.
If you have any questions, ask :)