While I agree completely about the site's potential, the word "potential" or "capable" can be dangerous without a reasoned approach. The thing to remember is that no matter how novel the tech, social sites are 100% a crap shoot.

Facebook is what Facebook is not because its tech, that came later. Its what it is because it nailed one of the most brilliant rollout strategies ever pulled of by a social site and established itself with existing real world communities, namely ive league schools to start, which let it concentrate on growing the network effect within each community before moving onto the next roll out.

Maintaining a reasonably high network density among real world peers/social groups is key to getting anything like this to grow long term. While Steemit has a lot of things working in its favor over other social sites, its important to remember that attrition is still going to slow down gains without people being able to make meaningful connections (which isn't to say they wouldn't...I've been enjoying myself here but I'm very much in the current target audience:P).

Whether they're meaningful because you already know them like FB, or they're meaningful because you share an interest in the same topic like Steemit/Reddit is irrelevant, but the key part is that people need to feel they're getting more from the community than they're putting in or they'll bail. While STEEM adds some extrinsic motivation that I think will go a long way to help the community seed itself to new audiences, extrinsic motivation without the addition of intrinsic motivators doesn't work as a strategy for long on its own.

So I guess the TL;DR would be that the success of any community can only really be determined by how well it manages to break down barriers with other existing communities to pull them into the fold. Facebook did that by targeting ivy leagues in part through their mailing lists, and in part through just a dedicated focus on chunks of schools at a time. Given Steemit is ultimately a different beast and not locked down by email domain, my guess is that Steemits biggest advantage would be to focus on a topic at a time, pull existing communities related to that topic into the fold, and only once each group of topics is seeded move onto pulling in the next group of communities.

Don't count your chickens before they hatch ;). I want to agree that this place is headed straight for the mun, but I've also been down the road of a failed community startup before so I know its not just a "make it and they will come" scenario. The success or failure of social services is far more people related than tech related in the end.