by veen

But Ethereum has also won fans with its promise to do much more than Bitcoin. In addition to the virtual currency, the software provides a way to create online markets and programmable transactions known as smart contracts.

The system is complicated enough that even people who know it well have trouble describing it in plain English. But one application in development would let farmers put their produce up for sale directly to consumers and take payment directly from consumers. There are already dozens of functioning applications built on Ethereum, enabling new ways to manage and pay for electricity, sports bets and even Ponzi schemes.

(title is the print title of the article, don't blame me)

mk, what do you think of this comment on Hacker News about Ethereum?

Ethereum becomes useless as soon as it interacts with the real world. Its brave new world of digital contracts works fine for creating simple gambling games or 'provably fair' Ponzi schemes, but as soon as a piece of code on the blockchain has to rely on a real world piece of data, you lose all of the benefits of the system.

You want to write something related to (say) a share price, or property ownership? Then your code needs to trust an external system providing the data, and the users need to trust that other people will honour the 'facts' decided by your program on the blockchain.

You want to create even a simple system that opens a lock when someone pays money? (The much-hyped Slock.it startup selling 'smart' locks) The blockchain makes no promise that a physical lock will operate based on bits in the blockchain. You have to trust that someone isn't cheating you.

And why is this need for extra trust a problem? Because once you require trust, you are back into the real world where we already have real solutions to these Ethereum based problems, that rely on trust (e.g. Share dealing, property sales, etc). By moving onto the blockchain, you have gained nothing and only complicated matters.