I'm pretty sure any digital information can be put on a blockchain.
This has been tried numerous times, and it either ends up with gargantuan amounts of blockchain bloat and/or a blockchain full of links to illicit content - hence my comments about the voting mechanism... In order for a bad actor to get dodgy data into the blockchain, they'd have to 51% the network... This would be greatly reduced if we offer staking, as we don't even need miners by that point.
The Bitcoin blockchain is already too big to download. Electrum figured out how to use specialized servers that index the blockchain:
Instant on: Your client does not download the blockchain. It uses a network of specialized servers that index the blockchain.
http://electrum.qc.to/It is open source..