One of the lightly-advertised changes in HF20 is that the voting calculation will change a little bit to adjust for the fact that SP-based bandwidth is going away and many new accounts will start with 0 SP. This will lead to a lot of votes lower than the dust vote threshold, and the system needs to handle that somehow; what the developers have decided to do is just not count the first fifty million rshares of everyone's vote.
50,000,000 looks like a big number, but in the case of rshares it really isn't. Right now that's a vote equal to about $0.000067. So if you're voting on your own in reasonable percentages, this really won't make any difference to your Steem experience, and I'm sure that's what the developers were thinking about when they did things that way.
However, it is a tiny penalty placed on those who vote more often, and one place where that can really matter is in curation trails, where people are often giving extremely small votes already with the expectation that they will count. I wanted to take a look at what's generally the most-notable curation trail on Steem, the one belonging to 
If you've gotten a Curie vote, you know very well that it's not just one vote. The curation trails votes just pour in, and if you've got Ginabot notifications it can be pretty overwhelming. A main-line Curie vote brings over 800 votes with it, and the subsidiaries are still 125 or so. Even their very tiny votes have 50 followers.
(I made a units error in the original version of this post; it has been corrected below.)
The effect starts to be a little bit noticeable at that scale. Every main-line Curie vote would lose about five cents total under HF20 with current prices. Just looking at yesterday, Curie handed out 22 votes greater than 10%, 52 votes at single-digit percentages, and 144 votes at 1% or less.
But when we include the curation trails the number balloons: that's 31300 votes being used to make up a full day's Curie payout, which is a startling 1.565 trillion rshares lost to the floor. That's equivalent to a 100% vote from a large dolphin with about 38,650 SP, or around $2.17 less every day that Curie collectively will be handing out in rewards.
Maybe that's still not a huge deal, but it's no longer completely trivial. A little bit of that will come back in increased rshare value, but most of it will be distributed to accounts that vote with higher percentages less often and thus lose fewer rshares to the floor. Since that's most of us maybe you can see that as a good thing. But in general curation trails are going to lose a small chunk of their value in HF20, and I'm not sure anyone really is paying attention.