Metaphors to Describe Bitcoin and Blockchain

[Trcream]

When you tell most people about a public ledger and a cryptographically secured cryptocurrency they look at you wide-eyed and confused. Metaphors are an excellent way to explain something complex to someone in a simple manner. By using something that they already know, they can associate and correlate the information they already have in their heads. For example, finding a good employee is like "finding a needle in a haystack". People can instantly relate to what it's like to find a "needle in a haystack".

So what good metaphors/ analogies are there to explain bitcoin and blockchain?!

Example: Blockchain is kind of like a shared google document, everyone can see what is happening but only one person can make an edit at a time. Also, once an edit is made, it can't be changed.

What else do you guys have???

[Kakmakr]

Bitcoin is like digital Gold, it dropped the weight and it is travelling via the internet from person to person and are being tracked by a online ledger that are stored in a decentralized technology called the Blockchain. The Gold still retained it's value, but it is just a digitized token now.

That should be easy enough, right?