Are there tasks that would be hard in a Solid or Blockstack app that are solvable with Ethereum?

Or applications that would be reasonable in Solid or Blockstack that would be impractical in Ethereum due to performance?

Ethereum's use of a block chain and a currency clearly makes it convenient for some situations in which money needs to change hands. Are there non-finanical situations in which a block chain is a win?

How does the mechanism in the "Decentralized File Storage" section prevent storage providers from cheating?

Would it make sense to build a chat system on Ethereum? A Piazza clone? A Reddit clone?

For the voting tutorial, you might find this document useful:

http://solidity.readthedocs.io/en/latest/introduction-to-smart-contracts.html

What happens when you install a new Ethereum contract?

Where is a contract's state stored?

How does one call one of a contract's methods?

How does the contract manage to update its state?

Can an Ethereum contract have private data, that only the contract can read?

Can anyone at all call a contract's methods? Is that a security problem?