| It's a public database. That's it. Anybody can write to the database and anybody can read from it. The problem is that whenever you have a public anything there will be spam. People will come along and they will fill the space up with scam ads and porn and hate speech. See: the internet. To prevent the database from filling up with spam you need to find a way to make people "pay" for writing to the blockchain. Nothing is free and if you're going to consume resources (storage and cpu) from other's computers then they ought to get something in return. That's what "transaction fees" are and that's why they're measured in costs per byte -- the people who are writing to this public, decentralized, highly resilient database are being charged storage fees. So blockchains are the solution to spam. And unlike pre-existing spam solutions a blockchain doesn't require storage/delivery nodes to "whitelist" certain certificates or for certificate authorities and CRLs and all that wackiness. This is kinda remarkable. This innovation enables all sorts of new models of collaboration (read: business models). Just today I saw a very interesting proposal for an Uber-like system built on a blockchain. Everything -- requests for transport, driver availability, driver fees, driver certification, passenger and driver ratings -- gets stored in the blockchain. Anybody can read, anybody can write. Here's the database, here's the type of "transactions" (records) -- go crazy. The interesting thing about this system is that it doesn't rely on huge bureaucracy to protect the database. (And what are many business firms but database maintainers and protectors?) Write whatever you want -- write pics of your cats if you like -- but it's going to cost you. (There's another element of what's commonly called blockchain which is "block verification." The problem here is that when everybody has a copy of the database how do you decide whose copy of the database is authoritative? This is the concept of consensus and note that it's only a problem if the peers in the database don't trust one another. It's actually not so interesting but it is largely an implementation detail of public blockchains with different strategies proof-of-work, proof-of-stake, electoral-validation etc.) |