Recently, there's been a few books and some startups based on the idea of "blockchain" based databases (not altcoins). Some people talk about private blockchains. Microsoft has a "Blockchain as a Service" offering (I read the marketing page and still couldn't figure out what that was). Factom bills itself as a "scalable data layer" for the blockchain. MediaChain is building a "blockchain" for media attribution. "The Business Blockchain" by William Mougayar talks at length about how blockchains will revolutionise business without ever addressing the technical challenges. Chain.co " partners with leading organizations to build blockchain networks that transform markets" (what does that mean?).

I read the Factom paper and wasn't convinced. I like the "anchoring to the Bitcoin blockchain" approach but without a decentralised consensus mechanism of the Factom chain itself, it doesn't seem like much more than a glorified Bitcoin based time stamping system.

MediaChain is even worse in that it hasn't even addressed the consensus problem in their white paper at all, arguing that such a thing will only be needed for "scaling". As far as I understand, MediaChain is the central authority which decides which chain is valid, which is kind of the anti thesis of a blockchain. They might as well have written a REST API.

I don't mean to sound so pessimist. Notable exceptions are Ethereum which has interesting technology and addresses the decentralised consensus problem. Or "colored coins" which leverages the Bitcoin blockchain and has interesting applications.

Anyways, I'd love if someone could convince me otherwise. Am I wrong in my analysis? Are there "blockchain" based database that sound promising?