Co-founded by Tyler and Cameron Winklevoss, Gemini is a fully regulated licensed US Bitcoin and Ether exchange. That means Gemini’s capital requirements and regulatory standards are similar to a bank. Also, all US dollar deposits are held at a FDIC-insured bank and the majority of digital currency is held in cold storage. Gemini trades in three currencies, US dollars, bitcoin, and ether, so the platform does not serve traders of the plethora of other cryptocurrencies. The exchange operates via a maker-taker fee schedule with discounts available for high volume traders. All deposits and withdrawals are free of charge. The platform is only fully available to customers in 42 US states, Canada, Hong Kong, Japan, Singapore, South Korea and the UK.
ErisX is a CFTC-regulated derivatives exchange and clearing organization that will offer digital asset futures and spot contracts on one platform. By integrating digital asset products and technology into reliable, compliant, and robust capital markets workflows, ErisX will help to make digital currency trading even more accessible to investors and traders, like you.

Namecoin: In 2015 Namecoin looked promising, here in 2017 there is a little less hype. Still, Namecoin is notable. Namecoin is almost the same as Bitcoin. It was the first “fork” of the Bitcoin software. It’s based on Bitcoin and has the same unit cap, but has a few tweaks in its data storage. Namecoin was originally just going to be an upgrade to Bitcoin, but people were nervous that it would pose issues. So Namecoin is similar to Bitcoin, but like all the currencies that are not-Bitcoin, it is worth a fraction of Bitcoin. Its solid background and reasonable price point make it a relatively good coin to invest in. Of all the coins noted so far, Namecoin has performed the most poorly so far. It is still priced very low in USD.
The market of cryptocurrencies is fast and wild. Nearly every day new cryptocurrencies emerge, old die, early adopters get wealthy and investors lose money. Every cryptocurrency comes with a promise, mostly a big story to turn the world around. Few survive the first months, and most are pumped and dumped by speculators and live on as zombie coins until the last bagholder loses hope ever to see a return on his investment.
Cryptocurrencies have been compared to Ponzi schemes, pyramid schemes[77] and economic bubbles,[78] such as housing market bubbles.[79] Howard Marks of Oaktree Capital Management stated in 2017 that digital currencies were "nothing but an unfounded fad (or perhaps even a pyramid scheme), based on a willingness to ascribe value to something that has little or none beyond what people will pay for it", and compared them to the tulip mania (1637), South Sea Bubble (1720), and dot-com bubble (1999).[80]
As of May 2018, over 1,800 cryptocurrency specifications existed.[24] Within a cryptocurrency system, the safety, integrity and balance of ledgers is maintained by a community of mutually distrustful parties referred to as miners: who use their computers to help validate and timestamp transactions, adding them to the ledger in accordance with a particular timestamping scheme.[14]