| Sure. Layers, like the Internet is made up of protocol layers. Bitcoin on-chain is layer one: slow, sure, and after 6 confirmations considered irreversible and immutable. Layer 2 protocols would include the lightning network and the liquid bitcoin protocols - both systems designed for different use cases, with differing technological benefits and risks. There may be other layer 2 systems that I'm not aware of. Some might consider the OpenBazaar marketplace protocol, the Open Timestamps (https://opentimestamps.org/) application, or the Bisq decentralized bitcoin/fiat exchange to be layer 2 applications, as they're built directly on top of bitcoin but includes protocols. But I think they're simple examples of the kinds of applications that can be built on top of the programmable trust-net that bitcoin represents. Because bitcoin is a decentralized and permissionless technology protocol, anyone who thinks of a way to build on top of it can do so---without needing anyone else's permission. Layer 3 might be applications built on top of layer 2, such as the censorship resistant Juggernaut chat app, built on top of the lightning network: https://www.getjuggernaut.com/. As layer 2 matures, I imagine we'll begin to see a wave of creativity unleashed globally as people create layer 3 applications. |