WCP: What is Blockchain, Bitcoin and Ethereum?

The blockchain is like the internet and 

Because of the nature and function of the internet, websites, social networks and apps can execute any function that can be expressed and done digitally.

The blockchain does for the representation, capture and transmission of value what the internet does for websites.  The internet enables a website, built on it, to fulfill the functions for which they were created.

The blockchain enables cryptocurrency built on it to represent, capture and transmit “value” [i.e., something that there is a market for]

Blockchain is to cryptocurrency what Railways are to Trains, 

Blockchain is to cryptocurrency what Cars are to Highways, 

Blockchain is to cryptocurrency what Airways are to Airplanes 

Blockchain is to cryptocurrency what the Ocean is to Ships 

There are vast varieties of makes and models for all of these vehicles, [i.e., cars, planes, trains and boats] 

And in each of them are niche markets for many different classes (people and needs) with different purposes and problems that specific genre of these vehicles solve. 

Just as there are a vast number of makes and models of all of these vehicles, [cars, planes, trains and boats]

And just as each of them serve different markets and each of them serve different classes with different purposes. 

SO, IT IS WITH ALTCOINS OR CRYPTOCURRENCIES