As you've probably heard, Bitcoin has hardforked again, this time into Bitcoin Gold. BTG uses the Equihash algorithm, which aims to "make mining decentralized again" by providing less benefit to ASIC mining and more to GPU, which is more common among everyday users. ASICs, or Application Specific Integrated Circuits, are specialized hardware that threaten centralization of mining and are many orders of magnitude more efficient at mining Bitcoin vs Bitcoin Gold.
The fork happened at block 491,407 this morning, Oct. 24 and was followed by a massive DDOS attack which brought the BTG website (https://btcgpu.org/) down for a few hours.
Support from exchanges is cautious. Coinbase sent an email stating they "may choose to support it" i.e. release coins created by users' Bitcoins held through the fork. They have yet to release users' Bitcoin Cash from the previous fork, although they've promised to do so on January 1. Hardforks in effect duplicate every existing coin onto both chains, although the value is seldom equal.
Bittrex said all Bitcoin (BTC) balances will be credited the equivalent number of Bitcoin Gold (BTG) coins but they will not provide trading options right away, citing lack of consensus code, replay protection, or adequate code for testing, as well as the obscurity of the developers involved with the project.
According to a statement, "Bitcoin Gold does not satisfy our criteria for safety for our users… Bittrex will make all reasonable attempts to credit our users BTG but until we have a fully supported wallet, we can neither guarantee tokens or consider creating a market. We will continue to monitor the state of the codebase and network."
The price of BTG fell from around $540 to around $210 on coinmarketcap today