Hello, Habr!
We hope not to shock you too much, admitting genuine interest in decentralized applications.

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Together with the author, we are convinced that the described technologies are useful for the “non-bitcoin one”, and as proof we propose a translation of an interesting article in which the prospects of the Blockchain stack are clearly and convincingly described.
I once had a chance to hold a workshop on the New York bitcoin hackathon, where I looked at bitcoin as a protocol, talked about alternative ways to use the blockchain, and also mentioned the challenges and opportunities associated with this technology.One of the main advantages of working in the field of venture capital is the opportunity to look at the markets from a completely new angle. Every day you can learn from businessmen and representatives of corporations how our future is being prepared - after all, they create it. It is fascinating, especially if you are a true techie.
We closely monitor everything that happens with Bitcoin and Blockchain. In some cases we are talking about ideas, in others - about real products that are already on the market. Some of them have burst, while others have raised funding in the millions of dollars. Having at hand all this information, you can identify certain patterns and trends and make an impression of what awaits us.

I think this is how the architecture of Internet applications will look like in 10 years. This is a simplified illustration, it does not show many important findings and problems. Below, I will try to explain its meaning as clearly as possible. In order not to be distracted, we will discuss each element of the stack from bottom to top, and then I will post on my blog a detailed article on each of them.
The idea is that all the components in the gray boxes are decentralized, open source. For now, let's call them Shared Data and Protocol Layers. Nobody controls these parts of the system, so they are accessible to any developer or company. So, in the case of Bitcoin, the level of shared data will be Blockchain, and the protocol will be the Decentralized Protocol.
You will notice that the higher you go up the pattern, the thinner the individual levels become. In addition, at the level of shared data and the level of protocols accounts for about 80% of the total stack. Modern applications for the Internet are created on the basis of open decentralized technologies such as TCP / IP and HTTP, but if you draw something like the diagram of the stack of Internet applications, as shown above, these open decentralized protocols will probably occupy only 15%, and above them there will be only private and centralized technologies.
1. Miners and BlockchainIf you at least approximately imagine how Bitcoin works, then you know who miners are. In essence, miners are nodes within a computer network, together verifying all Bitcoin transactions. The algorithm pays for their work bitcoins. Since bitcoins have a real quote, it is beneficial for the operators of these machines to work. If you are interested in how mining works, the topic is perfectly covered in
this article .
Blockchain is a public journal that contains a permanent record of all Bitcoin transactions; this log is kept by the miners themselves. It is not controlled by any organization and is accessible to all. Read more about Blockchain
here .
2. Overlay NetworksThis is where the fun begins. Developers are starting to build networks that run in parallel to the blockchain to solve problems that the bitcoin network cannot handle. True, with such tasks, the blockchain is also used - for example, to set time stamps or validate work.
One example of this is
Counterparty . The other, possibly Side Chains. Whatever form these superimposed networks have, they are all associated with the Bitcoin blockchain, and also use its network effects to gain flexibility; while they do not need to create their own cryptocurrency and / or block chains, as required by alternative solutions like
Ethereum .
3. Decentralized protocolsThanks to Blockchain, the opportunity to develop free decentralized protocols with built-in data validation (thanks to overlay networks and blockchains), as well as to make transactions that are not centrally controlled, was first introduced. This is where the traditional architecture of the IT business begins to break up.
The best example of a decentralized protocol that works on top of the shared data level is Bitcoin; we already imagine how he influenced money and finances.
Companies such as Ebay, Facebook and Uber are very expensive because they make huge profits on network effects related to storing all user information in private cells and getting a percentage of all transactions. Decentralized protocols located on top of the blockchain, potentially allow you to disable any individual part of the stack, so these services are very valuable to consumers and investors. To do this, for example, you can create shared decentralized data sets to which anyone can connect and start peer-to-peer transactions on the principle of Bitcoin.
In fact, many promising teams have already begun to develop protocols that can destroy the business models of the aforementioned companies. Example -
Lazooz , a protocol for searching for fellow travelers in real time; another example is
OpenBazaar , a protocol for free decentralized peer-to-peer markets.
4. Free and commercial APIsThe average developer is difficult to add code directly above the protocol, so you can easily connect to them. Whether this is good in the long run is a difficult question, but I believe that this is a very important part of the stack. The greatest achievement of these decentralized protocols is due to the fact that a developer with any set of skills and qualifications can quickly build applications on them and experiment with them.
It is either about commercial services or free projects. Good examples are API Chain.com and Coinbase Toshi for Bitcoin. Both are designed for the same purpose, but Chain is a leased commercial service, and Toshi is free.
5. ApplicationsThis is the part of the stack facing the user. In most cases, applications built on such an architecture will functionfully resemble existing ones today - just like Coinbase and PayPal. But the big difference for users is that the protocols in this case are decentralized. Programs will be able to exchange information exactly like different email applications or bitcoin wallets.
An important feature of this stack is that it grows from bottom to top. First there were miners, blockchain and bitcoin, and then everything else. As far as I know, the most important technological revolutions developed in this way.
Thus, there are very interesting challenges for developers, entrepreneurs and investors: after all, this stack adapts very promising things for mass consumption. But, ultimately, the user wins, because such applications have reduced or zero input fees, switching costs are small, all data are individually available, and market capacity exceeds all expectations.