I would like to know if developers can build apps on Steem for content creators and curators and be paid a part of the steem rewards for the content? This would make building social networks profitable without the need for advertising.

I can't find answers anywhere!

Also, an upvote on a Twitter replica site can mean much less than an upvote on a Yelp or Couchsurfing replica site... Can app builders manage the distribution of Steem rewards differently on their platforms?

In Steem, is an upvote is an upvote is an upvote? Are all upvotes equal no matter what the context? I mean sometimes a small number of upvotes can be of much higher value. Can the upvote system be more sophisticated without creating more cognitive overhead?