utopian.io […] via proof-of-brain

Proof-of-brain which I see is also mentioned on the Utopian website, is as I had explained in 2016 a very corrupt and flawed design that can never be fixed because the problem is not in the code but in the vested interests structure that requires the various non-objective aspects of Steem that enable the perpetrators to hoodwink everyone here.

Also the term proof-of-brain is by implication conflating the consortium DPoS blockchain design with the algorithm employed for minting rewards out-of-thin-air. Steem has delegated proof-of-stake consensus, not proof-of-brain. It’s technobabble employed for embellishment marketing to put lipstick on a pig, i.e. it is dishonest marketing babble that confuses n00b users and makes them excited to support something which is actually highly flawed.

You haven't covered much of how large the ecosystem actually is.

I am wondering how large is it?

utopian.io. If you have a quick look at https://steemprojects.com/ there are apparently 337 apps and tools for Steem

I perused many of them and they seem not that compelling. Utopian will not be useful until the upvote buttons can be embedded into the Github Issues threads and such so more eyeballs can vote. Ditto most everything else there doesn’t really have am effective adoption model. I don’t think Steem has enough adoption to drive Dtube, but I might be mistaken. Video and music is very problematic because of copyrighted material that can be embedded (such as a jingle tune in the middle of the video which was sampled from some copyrighted audio). Doesn’t seem like a low hanging fruit use case to chase, at least not until ledger servers are not run by elected witnesses that can be targeted by the authorities for hosting copyrighted content. Yet another one of the reasons that I think consortium blockchains are not sustainable.

My opinion is that as it become simpler and simpler for normal people to access these promotion services the competition will move from bidding skills/gambling toward creating extra value from the earned exposure on your content. The quality of the front-page will then increase along with demand for landing on it. (Trust me, very smart peoples are working towards that)

I agree with @cryptovestor that organic growth is what builds community and stickiness. And I amplify his skepticism further more towards the cynical w.r.t. to your non-sober embellishment and hyperbole. Lots of very smart people have been thinking about this and realized the voting from a collective pool can never work. It is a fundamentally insolubly flawed game theory structure.

OTOH, I recognize that @cryptovestor is correct in making the point that Steem is the only crypto project with a significant and enthusiast community (but I don’t how large?). One thing I am concerned about is if Steem fails and all these enthusiast people become jaded and disillusioned. I hope we can do something so they will not leave crypto forever if Steem flames out.

I see Steem as a very active reactor of economic activity with a social component that makes it's future applications at a high risk of going viral and attracting a lot of external interest.

Not if new users can’t signup.

Disclaimer: I have a vested interest in competing against Steem with the project I am working on.