Go to Trending and see for yourself. No more posts containing a few tilted phone camera pictures and at most a dozen lines of text boosted to the lower Earth orbit. The platitude-filled posts by a certain artiste are nowhere to be seen. Mostly announcements and decent content curated by large app accounts that have quality control such as ThreeSpeak. Low effort content has been extensively downvoted.
It's starting to look as if the free downvoting pool is working. Partly this is #newsteem that has brought about a newly found enthusiasm for quality control. I also have no complaints about the 50/50 curation despite my posts earning less because of it.
I turns out the posts enter the linear part of reward curve only when they hit 20 STEEM in worth. That's a pretty high figure in my opinion. I imagine it can be hard for newbies to get much traction when the threshold is that high depending on the degree to which the curve is sub-linear. Is there a more detailed explanation anywhere? Strangely, I still haven't found my own posts to be affected very much despite being firmly in the sub-linear zone save for a few better posts boosted by @ocdb here and there.
By the way, there is one thing that makes downvoting bid bot abusers' posts much less likely to attract retaliatory downvotes than you think. It's the fact that most of these people have never really networked on Steem and have no friends.