Different criteria can be used to determine which cryptocurrencies are the most popular. No matter which criteria is used, everyone would agree that Bitcoin is most popular and there are a number of reasons for this. It was the first cryptocurrency in the world, it has unique properties, the transaction speed is really fast in Bitcoin, no third party is involved in any transaction and people recognize that Bitcoin is the safest way, among cryptocurrencies, to save money.
One criterion by which to rank the popularity of cryptocurrencies is their market capitalization. Market capitalization is one way to rank the relative size of a cryptocurrency. It's calculated by multiplying the Price by the Circulating Supply. Price is calculated by taking the volume weighted average of all prices reported at each market. Circulating Supply is the best approximation of the number of coins that are circulating in the market and in the general public’s hands.
On February 22, 2018, Bitcoin was first on the list of cryptocurrencies with the biggest market cap among cryptocurrencies. The second place was held by Ethereum. The first thing about Ethereum is that it is not just a digital currency. It is a blockchain-based platform with many aspects. It features smart contracts, the Ethereum Virtual Machine (EVM) and it uses its currency called Ether for peer-to-peer contracts.
The third place was held by Ripple. Ripple is the name of a payment network and the payment protocol which powers it. It was developed and released in 2012 by a company of the same name, in order to enable "secure, instant and nearly free global financial transactions". It is built on principles similar to those of Bitcoin, so many people consider it a cryptocurrency. However, unlike Bitcoin, the source code of Ripple's technology is owned privately by the company, which means that it cannot be verified by an outsider.
Next in line are Bitcoin Cash, Litecoin, Cardano, NEO, Stellar, EOS, Dash, respectfully.