[nicholas-cc]

It seems like if you choose to record transactions to the blockchain you end up posting every transaction to the blockchain which is quite expensive; why not only store the hash of the HTTP request and use a Merkle Tree to store multiple requests in a single Bitcoin transaction? The only reason I see why not is that then the actual request data could be lost or not revealed, but since this protocol saves all requests to an internal database as well, I don't see why that would be a problem.

[miked85]

The first sentence of the introduction paragraph states that transactions are offchain:

"Vapor is an OFFCHAIN Bitcoin protocol for building a decentralized web by "Bitcoinizing" HTTP requests"

[mrschwabe]

further down however, it indicates you may also optionally post onchain ie- to take advantage of a blockchain backed timestamp.