Right now, most websites are hosted on just a few dozen host providers. Many smart contracts refer to databases. Some require storage. If data was stored on centralized servers, it can easily become a one point failure for many systems. Siacoin is a project which aims to decentralize storage. Lots of data space around the world goes unused. Sia lets buyers and sellers of this unused storage meet. There are no restrictions on who can buy storage. One piece of document can be stored on many computers to provide redundancy. As all files are encrypted, your data is completely safe from prying eyes. As there is a lot of unused space, competition is high, so prices tend to be cheaper than normal cloud hosting providers.