Introducing Web 3.0
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This course explores the theoretical side of blockchain technology as well as the practical elements. You'll learn what the blockchain is and the difference between private and public blockchains. We'll also cover smart contracts, and Web 3.0.


Blockchain technology is often grouped into being a part of the Web 3.0 era. In this lecture, I'll be discussing just what the Web 3.0 era actually entails. So, traditionally we are talking about the centralized web that we all know as app developers. In the centralized world, you usually have a server and this server serves the website for example. There are a number of definitions what the Web 3.0 really is. O'Reilly defines it as the evolution of the rather static Web 3.0, where we have a lot more user generated content. Nova Spivack defines it as a connective intelligence, while some others call it the semantic web. Recently, the term Web 3.0 was more and more connected with more decentralized services. So, it's safe to say that we can refer to Blockchain technologies and the decentralized web when we're talking about the Web 3.0. In the decentralized web, there is no more centralized server. In the decentralized web, we have a couple of nodes that interact with each other and replicate the content in a cryptographically secure way. The centralized servers with our traditional architecture is usually referred to as the Web 2.0. The decentralized way of serving information can also be referred to as the Web 3.0. In the decentralized world, there are a number of services that are available. These can range from simple file sharing or message exchange to complicate services via a Blockchain and smart contracts. What about the characteristics of the Web 2.0 VS Web 3.0 era? Well, when we're talking about the Web 3.0, then we mostly refer to the decentralized web. In the decentralized web, most services run via a Blockchain. Ethereum is one of the biggest Blockchain serving so called dapps or Distribute Applications. On the Blockchain, every bit of information is saved in blocks which cannot be altered afterwards. So, it is a transactional hierarchy of information. Information can only be added. Now, this doesn't necessarily mean that we can't delete anything anymore for programs running on top of it, it's just recorded on the Blockchain that it was created first and then deleted again. So, it's obvious to anyone what happened with every bit of information from start to finish. This is one of the biggest differences between the Web 2.0 and the Web 3.0, immutability. When we are talking about the decentralized web, then we mostly talk about decentralized applications running on smart contracts. The Ethereum Blockchain is the biggest player in the field, but why is Bitcoin so important then if it can't run any distribute applications? Because with Bitcoin you get one single distribute application, that is, value transfer, and this is said to be the biggest competitor to the financial services industry. If you send remittances today you pay average around 5% fees using traditional financial services, sometimes much higher. With Bitcoin, using decentralized value transfer in a cryptographically secure way, these fees could be lowered drastically against typical Web 2.0 financial transfers for a centralized server. But today, there are much more possibilities on the decentralized web from self governing code, to decentralized data storage, to all kinds of services on top of it. There is a plethora of new things coming towards us. Now, when did this transaction from the Web 2.0 and 3.0 era take place? So, we're all very used to our traditional client-server infrastructure. We open a browser and enter an address. In the most simplistic case, our browser will resolve the DNS to an IP address. Then, it will connect to the web server behind this IP address and download the HTML page, CSS, and images. This information is passed and displayed to the user. With load balancing and clustered server infrastructures, it becomes more complex but the principle stays the same. A client connects to a server and downloads the information, we have seen distributed information already long time ago with the tar network. Instead of downloading the information from one server, we suddenly connect to many different sources downloading bits and pieces of information from all around the globe. The Web 3.0 brings exactly this concept to the next stage and applies advanced cryptographics on top of it. Now, when you use Google, Facebook, Twitter, and so on, you enter your username and your password. This authentication and authorization process is so common that we barely think about it anymore. With the Web 3.0, you don't necessarily own  a username and the password anymore, you own a private and a public key. The private key creates signatures for every transaction you send off and this can be verified and bound to your account. But that's not all, you don't send it to any traditional server anymore. Instead, you could run your own Blockchain node on your computer, being your own server and client all in one. The difference is the consensus model. If you want to update information, then you have to convince every other node in the whole network that you are allowed to do so. This works with the private public key cryptography and complicated mathematical operations you luckily don't have to know about. So, when it comes to the transition between Web 2.0 and Web 3.0, then we have to rethink about how we see the web. Instead of client-server, we suddenly see distributed information that can only be changed with the right private key. Everybody is suddenly a server and everybody a client, but only those people with the right private keys can change the information. This can range from simple text, numbers, and bulletins, to chat message decryption, to file sharing. It all starts with the transition to mass decentralization of information and private public key access. And to really give a zoomed outlook of how all this happened, let me go over the past, present, and future of the web. So, the Web 1.0, I remember sitting in a bus to school reading the first HTML 4 book. It was so exciting, I could write some code and upload it to a server. Then, someone would type in my website address anywhere in the world, download the website and see what I coded in HTML and a little bit of CSS. The problem was that nobody could change that information. It is one way only so a static website. Obviously, it wasn't enough. At some point, people started to create databases and dynamic websites, Solich forums, galleries, chats, and so on. It all required some code on a server to digest the information from other users, store and retrieve it from some database. The Internet is inherently an unsafe place, we saw it with ecommerce. You might remember those horror stories where someone would order a laptop and receive bricks instead. This led to the rise of intermediaries, such as, Paypal with biprotection and so on. We constantly tried to make the Internet a safe place. With so much dynamic content and an ever growing web which becomes faster and faster every day, we started to get search engines to make sense of all this information. The Web 2.0 was born, an interactive place where everyone could participate. The Web 3.0 aims much more security, privacy, trust, and transparency. It aims to remove the necessity for such intermediaries and government stepping in. It aims and self-governing code and having code and economics run on the same systems in a secure, traceable, immutable, and unhackable way. The next generation of the Internet will not be fundamentally different from the way we use it now. There will be readable content, writable content, things you can interact with, things that you can download, but it will come from different sources, with different privileges, and different ways to access that information. So, there we have it, a super in-depth lecture on helping you to understand the Web 3.0 era. I look forward to seeing you in the next lecture where I'll be explaining the Blockchain that we'll be working with on a practical level as we move forward.


About the Author
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Ravinder is an expert instructor in the field of cryptocurrencies and blockchain, having helped thousands of people learn about the subject. He's also the founder of B21 Block, an online cryptocurrency and blockchain school.

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