What kind of applications can I run on blockchains?

I want to conclude this chapter by going over some of the applications that you can imagine running on some of the public or private blockchains currently available. The most widely-used or anticipated public blockchain platforms on which to run your own decentralized application are Ethereum and Blockstack.

• Ethereum: One of the longest standing platforms in existence is Ethereum, an open platform that lets you build, run, and use decentralized applications using the blockchain technology. This decentralized platform runs applications in the form of smart contracts; that is, applications that run exactly as programmed without censorship, fraud, or interference by a third party. These smart contracts consist of computer code that can facilitate the exchange of anything of value, such as currency, content, property, or shares. Because of the decentralized nature of the platform, there is no possibility of downtime.
• Blockstack: One upcoming public platform is Blockstack, which aims to be the new internet of decentralized applications. With Blockstack, users own their data and maintain their privacy, security, and freedom, instead of the application provider. In addition to the platform, Blockstack also has its own browser in which you can access the available apps. It uses the already existing lower level of the public internet, but applications are serverless and decentralized. Blockstack also provides a decentralized domain name system (DNS), decentralized public key distribution system, and registry for apps and user identities.

Either of these platforms lets you build applications. Ethereum is more basic and broadly accepted, but it only supports smart contracts (backend code). Blockstack, on the other hand, is a platform for decentralized applications that contains both frontend (web application) and backend (smart contracts).