Bitcoin's Lightning Network
Bitcoin has a 7 transactions/second limit, far too low for becoming a major payment provider (VISA handles on average around 4000 transactions/second). So how can we solve this?
One of the proposed solutions is by using the Lightning network. This reduces the load on the main blockchain by letting small transactions happen off-chain. By using this network, you directly exchange money with a counterparty, without hitting the main blockchain. Scalability through this system is virtually limitless.
Sources
A Primer to The Lightning Network (Part 1). (2017). ecurrencyhodler. https://medium.com/the-litecoin-school-of-crypto/a-primer-to-the-lightning-network-part-1-be909c403bde
Fyookball, J. (2017). Mathematical Proof That the Lightning Network Cannot Be a Decentralized Bitcoin Scaling Solution. https://medium.com/@jonaldfyookball/mathematical-proof-that-the-lightning-network-cannot-be-a-decentralized-bitcoin-scaling-solution-1b8147650800
Hertig, A. (2017). Lightning Can Scale Bitcoin, But Are Costs a Barrier? https://www.coindesk.com/will-bitcoins-lightning-network-used/
Multisignature. (n.d.). Bitcoin Wiki. https://en.bitcoin.it/wiki/Multisignature#Multisignature_Wallets
Nadeem, S. (2017). What You Need to Know About the Future of Bitcoin Technology. https://medium.freecodecamp.org/future-of-bitcoin-cc6936ba0b99
Scalability. (n.d.). Bitcoin Wiki. https://en.bitcoin.it/wiki/Scalability
Torpey, K. (2015). A Simple Explanation of the Lightning Network. https://coinjournal.net/a-simple-explanation-of-the-lightning-network/
Visa Inc. Facts & Figures. (2017). VISA Inc. https://usa.visa.com/dam/VCOM/global/about-visa/documents/visa-facts-figures-jan-2017.pdf