Etherscan.io is a site that lists smart contract statistics, code and other interesting features of the ethereum blockchain network. It mostly lists applications running on the main-net.
As of date, there are about 17500 verified smart contract with source code listed. An example is here. As can be seen the source code written in the solidity programming language is complex and has logic that consists of loops and other constructs. Most of these smart contracts are for new token offers (ICOs). A few of them, however, are for unique applications – like that of Cryptokitties or game related apps.
That being said, it is not entirely surprising that the ICO market raised 4.5 Billion dollars last year compared to 1.5 billion dollars in VC, seed and angel financing for blockchain and smart contract related companies during 2017.
Smart Contracts – 1 Million+ and counting
However, not to discount the whole smart contract space, The 17000+ listed smart contracts in Solidity are not the only smart contracts that exist on the Ethereum Blockchain. Several of these smart contracts exist on the ethereum blockchain as byte-codes or executable versions of solidity code, that the authors chose not to release as open source. Since the ethereum blockchain is public and can be downloaded scholars have studied them in detail looking for vulnerabilities.
There are more than 1 million smart contracts that have been studied for vulnerabilities, and this number according to this paper has grown 100 fold in just 2017. The distribution of ether – i.e. 1% of the smart contracts locking in 99% of ether makes this network’s distribution very skewed.
Even if 1 smart contract were to be vulnerable – as is possible this would be a huge risk to the ecosystem. The team at NUS- computer science has created a tool, that can scan the bytecode of smart contracts from the ethereum blockchain, and test it for vulnerabilities. So far they have found about 34000 smart contracts to be vulnerable according to this paper.