Payouts are separated into the author reward and the curation reward
Author is guaranteed at least 75%
Up to 25% goes to curators (people who upvoted the post)

Author reward is paid out:

• 50% in Steem Dollars
• 50% in Steem Power

Curation rewards are paid entirely in Steem Power.

WHAT DETERMINES HOW MUCH OF THE CURATION AWARD GOES TO THE AUTHOR vs. CURATOR?
It all depends on how long after posting, the vote was cast:

• If a post is upvoted the moment it's posted, 100% goes to the author
• If a post is upvoted 30 min after posting, 100% of the curation award goes to the curator.
• Between 0 and 30 minutes, each moment that passes, more of the reward goes to the curator.
  At 15 minutes it's a 50/50 split.
  At 3 minutes, 90% goes to the author and 10% to the curator
  At 27 minutes, 10% goes to the author and 90% to the curator

I'M UPVOTING POPULAR POSTS AT THE RIGHT TIME, WHY AM I NOT GETTING ANY CURATION AWARDS?
Curation awards are based on the square of your Steem Power
Example:
Bob: 10 SP, the square is 100.
vs
Jim: 100 SP, the square is 10,000
In this example, Jim has only 10 times more Steem Power than Bob, but Jim will get 100 times higher curation award than Bob, all other things equal.

• Double your Steem Power, get 4x the curation award
• Quadruple your Steem Power, get 16x the curation award
• Increase your Steem Power by 100x, get 10,000x the curation award

AN HOUR AGO MY POST SAID IT WAS WORTH $5, BUT NOW IT'S ONLY WORTH $4. WHAT HAPPENED?
It could have been flagged which would bring the total down. But if it wasn't flagged...

There is only a select amount of Steem to be dispersed in a rolling 24 hour period. At any given time, the system is making an estimate of how much you will be paid based on what percentage of Steem Power-adjusted votes have been given to your post.

Let's pretend a post is currently worth $5. But then, a bunch of other posts starts getting really popular. That money needs to come from somewhere, so a portion of your post's value needs to be taken away and reallocated to these newly-popular posts.

Hope that helps to clarify some things!​