Hello buddy, thanks for your fine thoughts on this topic. Here is my response:

Except that one essencial ingridient: people's data. Steem is just not allowing to 'spying' on us well enough.

Yea, it is true that the aggregation of data is one fundamental key to advertisement on the social media. Advertisers want to reach out to specific group of people, true. I will not pretend to say that Steem can match the specificness of Facebook but I know that Steem can easily target people based on their geographical location and the communities that they people to. Also, tags can be used to reach out to people who share a particular interest. Pizza can be advertised on the food tags just like tickets can be sold on the travel tags.

So, I agree that Steem cannot be as precise as Facebook but we can offer what Facebook can't offer, that is, rewarding the consumers. Cheers!