1. Math Based Currency 

Major Contributor: BitCoin 

Year: 2009 

In 2009, Satoshi Nakamoto released the software of Bitcoin. It's the beginning of everything.  

 2. Blockchain 

Major Contributor: BitCoin 

Year: 2009 

Bitcoin uses blackchain to record transactions. Today the majority of cryptocurrencies are based on blockchain, and the technology is also at the center of many financial innovations.  

 3. Proof-of-Work Mining System 

Major Contributor: BitCoin 

Year: 2009 

Bitcoin uses proof-of-work system to make the blockchain consistent, complete, and unalterable. Even today in 2016, many cryptocurrencies still fully rely on the system.    

4. Proof-of-Stake System 

Major Contributor: Ripple 

Year: 2012 

In 2012, many cryptocurrency users still thought every new coin needed to be "mined" to make the system work. While Ripple might not be the earliest adopter of proof-of-stake system, its success clearly paved the way of alternatives to traditional "mining" based system. 

Today, out of the 6 most popular cryptocurrencies based on market cap, Steem, Ripple, and DAO don't purely rely on "mining" system to issue new coins, and Ethereum may switch in the future.  

 5. Smart Contract 

Major Contributor: Ethereum 

Year: 2015 

While Ethereum might not be first cryptocurrency implementing smart contract, it has become a leader of the field. Smart Contract may be the foundation of many fintech innovations.       

6. Crytocurrency with Mainstream Use Case 

Major Contributor: Steem 

Year: 2016 

In 2016, while many cryptocurrency fans show strong enthusiasm, math based digital currencies are still not widely accepted by general public. Some argue the industry lacks valid use case to average internet users. 

Steemit is rising quickly, and it may become the first cryptocurrency with a very large user base. Reddit has over 200 million unique visitors monthly. Even if Steemit can only attracts half of those, the 100 million user base will become a milestone of the industry.  

7. Crytocurrency Encouraging Long Term Stakeholders 

Major Contributor: Steem 

Year: 2016 

Steem uses Steem Power to encourage long term stakeholders. In my view, this will make the currency system more stable and user base more loyal. This may be a major breakthrough, potentially followed by many new cryptocurrencies.   

While the whole cryptocurrency industry has already $12.9 billion market cap, I think it’s still at a very early development stage.       

More Breakthroughs will come. We haven’t seen anything yet.