Coinmarketcap lists the top #cryptocurrency of the world. At the moment of writing, Steem is ranked number 18, and has been one place higher or lower the last few days.
This makes it one of the more important Proof of Stake (PoS) coins in market capitalization. The whole cache of Steem is now worth just above 355 million USD.
Cryptocurrency Art Gallery, CC0, by Namecoin
Compared to the capitalisation of #Bitcoin, almost 45 billion USD, that isn't a whole lot, but the top coins are mostly Proof of Work (PoW) which demands an extreme amount of energy to "work". Here are the top 20 coins, at the time of writing (2017-07-21), with their verification/validation system:
(Beware that I have here used the coinmarketcap.com main listing which mixes tokens/assets and currencies. Tokens/assets rely on another technology. EOS, for example rely on Ethereum and will not have its own blockchain before probably in 12 months. I will likely amend the post so that it only list currencies.)
- Bitcoin: PoW
- Ethereum: PoW (but with plans of migrating to PoS)
- Ripple: "Consensus ledger". PoS?
- Litecoin: PoW
- Ethereum Classic: PoW
- Dash: PoW(?)
- NEM: Proof of Importance (PoI)
- IOTA: PoW (but low difficulty, not comparable to typical PoW?)
- Monero: PoW
- Stratis: PoS
- EOS: PoS (being developed by one of the Steem founders)
- Veritaseum: ?
- Bitconnect: PoW & PoS
- Qtum: ?
- Bitshares: PoS
- Zcash: PoW
- AntShares: ?
- Steem: Distributed Proof of Stake & Subjective Proof of Work
- Waves: DPoS (Delegated Proof of Stake) & LPoS (Leased Proof of Stake)
- Tether: ?
You could find more information about the technologies for mining, verification and validation at cryptocompare and the Wikipedia list of cryptocurrencies.
It seems to me that identifying currencies that are bound to die off (because they are scams, or just have nothing to offer) and betting against them, could be an easy way of making money. Another characteristics that could be interesting to look into is whether a coin is open source.
Please do let me know if you have more or better information about any of the coins.