RT @CoinDesk: OPINION: "Five years later, all of the use cases envisioned by Vitalik have become a reality, though some with more success than others," says @CamiRusso, author of a new history of Ethereum's development.
Ethereum decentralized applications are like building blocks. They use structure and data from these previously established building blocks to build their own, incrementing value to the whole structure. It's commonly referred in the literature we see out there as composability.
You already have some examples out there, but I will give one example of something simple that will get traction: take Uniswap's features. Now imagine that you are the CEO of a gaming company that wants to allow users to have an in-game wallet in which they can deposit ETH, DAI, USDC or any other ERC-20 that they can use to buy in-game assets other users sell.
Imagine you want to allow your game's players to find in-game items they really want to have and others to sell items choosing which currency to accept. Now imagine a player is selling one for 25 DAI and another player wants to buy it. The latter player only has ETH in his wallet and need to convert some of it to 25 DAI in order to buy that said in-game item. All the game needs to do is have a connection to the ETH/DAI Uniswap pool and with a couple of taps the user now has the accepted currency to pay the owner of the item he wants to buy.
This feature relies completely on Uniswap, making Uniswap a building block in the whole structure. Your game only connects to it and use its pools to trade assets.
Just like in Minecraft.
This is also an example of emergence. Where the network has properties it's parts do not have of their own. Termite structures, ant colonies, ripples in the sand, fractals are all emergent properties. Even temperature. It doesn't make sense to talk about the temperature of a single molecule, as temperature is an average of many. In the same ways, the Ethereum network will have emergent properties thanks to contract composability. Things that can't exist on their own, but are made possible thanks to the building blocks made by others.