What is Sia.Tech
Sia leverages the capacity of blockchain technology to enable distributed networks to reach consensus in a secure and trustless way. Cryptographically secured smart contracts ensure the encryption and transfer of data with no possibility for a third party to interfere in any way.
Source About Sia.Tech
In short, it is a decentralised and trustless way of storing your data out of reach of prying eyes as well as away from centralized services Dropbox, Microsoft Onedrive, Google Drive as well as many other competitors.
How Does It Work?
Instead of all data centers being owned and operated by a single company, Sia opens the floodgates and allows anyone to make money by renting out their hard drive. Data integrity is protected using redundancy and cryptography.
There are two ways someone can bring about the Sia network and earn Siacoin. Instead of keeping all of your data in one place, it breaks up the data and distributes your files across many different servers, all over the world. It's a blockchain network storage service which provides high security and low expenses. A little network transfer fee may be charged. Contracts are facilitated through a blockchain very similar to Bitcoin, but with a couple modifications.
What's a Siacoin?
Sia uses a cryptocurrency, Siacoin, to enable decentralized payments via file contracts. All payments on the network happen in Siacoin, which is a critical component of our cryptographic SLAs. Siacoin allows us to do things that would not be possible with Bitcoin or traditional online payments.
Source FAQ Sia.Tech
Why Should I Care?
There are two main reasons you should care about Sia.Tech and Siacoin. Those who need redundant cloud storage for all of your personal data, and those who have drive space to share.
If you are in the latter, then you can rent out your unused hard drive capacity to the network, to be utilised by those who need storage. This way you both get something, a form of currency which can be traded or used with the network and the other person gets to store their cat photos.
Furthermore, the cost is far cheaper than traditional companies, with a current estimate that if you wanted to store 1TB in the network, that it would cost ~$2 per month.
In Summary
I suggest you go check out their Roadmap to see what they have yet to come, as the technology and the crypto-currency have significant value.