When people refer to the Factom Protocol as a "pure data" blockchain, what does that mean?

Q. When people refer to the Factom Protocol as a "Pure Data" blockchain, what does that mean and how is it different from other blockchains?

A. Alex from Factoshi answered the following here:
When people say that Factom is 'pure data', they mean that the content of entries do not contain any code to be executed on chain.

To give an analogy, Factom is much like a safe deposit box. You can put anything into a safe deposit box. The box won't do anything with its content. it will just sit there keeping it safe. Anything can go into a safety deposit box (as long as it isn't too big). The box doesn't care. It doesn't verify what the item is. It will just hold it. It also doesn't need to interact with any of the other boxes.

This is uncomplicated. It is simple. Software developers strive for simplicity in their design. Bugs are less likely and the network can typically scale more easily. Added complexity can be built later in second layer applications.

Ethereum, on the other hand, lets you execute arbitrary code on the blockchain. This is not simple data. It requires work and validation. Unlike an item sitting in a safe deposit box, the content of the transaction impacts whether the network will be able to accept it.

To give another analogy (this time seasonal), Ethereum is much like Santa's workshop. Transactions are the children's letters to Santa. They contain an instruction that Santa then puts his elves to work on. This is more complicated, it is more dangerous, and it takes more time. Unlike Santa's workshop, transactions on Ethereum are made even more complicated by the fact that they often have to interact with each other.

So, to summarise, Factom is pure data because the content of Entries do not contain any instruction to the blockchain. Whereas Ethereum is not pure data, because the content of the transactions contain code that must be executed.
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