Summarized version:

Posts that received very few votes, or small votes, will earn less from the rewards pool.

Posts that received many votes, or a few very large votes, will earn more from the rewards pool.

The point where the meet is roughly around 20 STEEM. So if your post pending rewards are less than ~20 STEEM, you should be doing everything you can to get more votes. Either buy using bid bots, or by writing better content, or by expanding your audience.

This, combined with increased curation rewards, now 50%, is supposed to incentivize people to vote more efficiently (on good posts that will receive more votes after yours) and to downvote posts they feel are over valued or spam. (the HF adds the ability to downvote a few times without losing any upvote power)