Transaction speed has always been a critical bottleneck which prohibits mass adoption of blockchain technology. Bitcoin can only process 6 transactions per second, and 15 transactions per second for Ethereum. However, Telegram Open Network seems to be able to tackle this problem and accomplish millions of transactions per second. According to TON's technical Whitepaper:
Almost all blockchain sharding proposals are “top-down”: one first imagines a single blockchain, and then discusses how to split it into several interacting shardchains to improve performance and achieve scalability.
The TON approach to sharding is “bottom-up”, explained as follows. Imagine that sharding has been taken to its extreme, so that exactly one account or smart contract remains in each shardchain. Then we have a huge number of “account-chains”, each describing the state and state transitions of only one account, and sending value-bearing messages to each other to transfer value and information.
So in this structure, TON is able to accomplish millions of transactions per second, which will make TON the first mass-adopted blockchain technology possible.