Ethereum is a blockchain technology coming out of the bitcoin sphere with the idea to offer general purpose computing not only as a limit script of a transaction but make it the primary purpose of the network. Similar as Bitcoin programs, there called "contracts", are stored in a publicly accessible blockchain anyone can copy and fork. An though contracts can reference one another and even call upon each other within its operations, the system itself isn't a good data storage solution.
However, the Ethereum Foundation was specifically created to foster innovation and research in the wider ecosystem around the Ethereum blockchain and its very first hire set out to build that missing reliable, storage mechanism - called SWARM. After two years of development the first SWARM client was published late 2016 and an alpha network is live. SWARM employs the virtual XOR-Namespace and Kademlia forward routing (as discussed in previously) to assign the responsibility of data to nodes. It also comes with its own pub-sub-notification protocol, call WHISPER, and through that offers live updates of data.
As the project is developed within the Ethereum ecosystem it also no wonder that SWARM is actually part of the default ethereum go client today - though hidden behind a separate command and not yet switched on by default. But by doing that the project allows for an easy upgrade path for the entire Ethereum network should it become stable - and could over night offer a lot of resources simply by being switched on in a newer version. The other part that is interesting about this, is that the project is directly linked to the Ethereum network, which allows it to solve the complicated problem of offering distributed computation as well. A subject that all other participants struggle with, if they have an approach at all.
Though it is necessary to say that, as it stands today, data is stored "as is" in the network. Neither the client nor the network employ much default privacy-preserving behaviour and it still needs to be provided by the apps on top. It does come with some nice and easy to use command line tools and http-to-network-proxy though, making it very easy to get started on it quickly. We'll see more about that when we attempt to upload websites to the various contestants.