Perhaps once of the most complex and hot market opportunities right now within the Block Chain ecosystem beyond identity is the notion of a global storage namespace, protected and secured by a(the) Block Chain. Numerous startups are vying for the hearts and hard drives of the masses in an effort to prove out the technology and capabilities needed to effectively accomplish a trust-less, purely distributed storage namespace. They all allow people to share out their unused storage space on their computers for currency and allow people that need storage to purchase it. Here's some of my (current) favorites.
First up is Sia. Sia fits squarely into this mold of renting and leasing storage using the concepts of purely distributed Block Chain technology. The UI for Sia is the most polished of the solutions that I've seen thus far and make it 'relatively' easy to rent or share out storage. Sia relies on its own Block Chain, of which each client is a member. I find a bit of fault with this approach from a usability perspective but from a solution perspective, it makes sense as they have more lower level control. The problem with Sia, as I mentioned is that each client (at present), must sync the entire Sia Block Chain to be useful. At the moment, the Block Chain is small, so it doesn't take long, but that will linearly increase with time which will bring to bear the need to have light clients or preseeded clients. The other issue is the monetary function of Sia is a bit cumbersome. Instead of using USD, Sia (like most other solutions presented here today) leverages an AltCoin, so one must convert from their national currency (like the USD) to Bitcoin (typically) and then to the Sia coin. There are exchanges out there that make the hop easier but it is still difficult relatively speaking. That being said, the Sia coin is generally well regarded already in the Block Chain financial markets. Additionally, Sia renters have to put up substantial collateral to provide storage and they don't recoup those investments for some time. This is annoying but positively essential - to lock up the collateral means renters are far more incinted to keep their environments up and running and not risk stability of the platform. Personally, I would take a different approach and make redundancy more of a focus so renters (called Farmers in this world) can come and go a bit more easily. I think the team rushed to their 1.0 release a bit fast but they continue to iterate at a great pace and it will be neat to see what they come up with in the future.
Second up is StorJ. StorJ is similar to Sia in function (storage renting and leasing) and is admittedly not as far along to a complete end to end solution like Sia is, but that shouldn't scare folks away as I believe the StorJ solution is more likely to have a long term success story. A few things to note about StorJ up front is that there is only and interface to rent out storage at the moment, there is only a CLI interface for leasing and using storage. That owes simply to the fact that StorJ is focusing on engineering a great platform and leaving it to others (for the moment) to provide interfaces on top of their API. StorJ is a Counterparty based asset which sits on top of the Bitcoin blockchain, so unlike Sia, mining is not something end user clients have to deal with. The 'client' won't have to download or ever touch the Bitcoin or Counterparty Block chain if they don't want other than for payments. In the payments sphere, it will be similar to Sia from a number of hoops perspective, however, when it is released. For the renters of storage, getting started is easy and the P2P network is advancing in maturity really well. Storage is free at the moment because it isn't released and the currency SJCX (again, a Counterparty coin) is already well regarded in the Block Chain financial markets. What I really love about StorJ is the time they are taking to get the platform just right. They have a long ways to go before I'd put my kid pictures on it, but progress is swift thus far.
Other solutions exist out there - actually dozens. I chose to cover a few of my favorites but please don't not look at tools like MaidSafe and IPFS. Both have similar structural benefits and weaknesses as Sia and StorJ and are married in one way or another to the notion of Block Chain backed security AND financial instruments to provide an incentive for people to share out their unused storage capacity for some small amount of money (sovereign, bitcoin or altcoin wise).