Vision of Polkadot
The Internet was originally designed for and built upon decentralised protocols such as TCP/IP, however, its commercialisation has led to the centralization of all popular web applications today. We refer not to any centralisation of physical infrastructure, but rather to the logical centralization of power and control over the infrastructure. A central entity controlling a system poses many risks for everyone. For example, they can stop the service at any moment, can sell users' data to third parties, and manipulate how the service is working without the users' agreement. This is in particular critical to users who heavily rely upon these services for business or private purposes.
With all the current interest related to personal data ownership, there is a growing need for a better security, freedom and control for net users, and with this a countermovement for more decentralised applications where no single entity controls the system. This tendency towards decentralisation is not new; it has been used in a number of areas of the development of web and other systems, such as the free software movement.
Blockchains are a recent technology proposed to address these problems, in the quest to build a decentralised web. However, it can only compete with the centralised web if it is usable for masses of end-users. One important aspect of this is that separate applications must be able to interact, otherwise each will become isolated and not adopted by as many users. Having to build such an interoperability mechanism introduces new challenges, many of which are missing in the centralised model because of the fundamental differences in the trust model between the two paradigms.