Ethereum is a decentralized application (dApp) and smart contract blockchain platform. Invictus Capital currently uses Ethereum to deploy smart contracts and issue tokens. It is arguably the most tested blockchain platform, and development is active and ongoing.
For a technical overview of how Ethereum functions at different levels, please see this Medium post.
Smart contracts allow us to do many different things. A smart contract is essentially a bit of code (instructions) stored, distributed and executed on the Ethereum blockchain. Ethereum's programming language is Turing-complete, which means that it can be used to carry out a wider range of functions, compared to, for example, what we can do with the Bitcoin blockchain. It is common to see simple crowd-sale contracts which allow fundraisers to issue tokens, though the possibilities are extensive. Invictus Capital utilizes a smart-contract to govern the liquidation option with Crypto20, for example - and this is accompanied by a more friendly user-facing dApp which carries out the necessary steps for you.
Please see the following resources for more detail: