It's not a fee taken from your rewards either, because the rewards are not yours until you are paid them, and this discussion is all about future rewards which aren't yours yet.

Technically all of the rewards of every kind come from inflating/diluting investor stake. With this fork, that money coming from investors will be spent a bit differently going forward is all. A lot of it will still go to content rewards. As @andrarchy says, ideally more of that will hopefully go to good content rewards. Some of what is currently coming out of the pool to fund projects will ideally shift over to SPS, leaving more of the remainder for content.

Overall it is very difficult to say what the net effect on any particular reward earner will be, but the goal here is not in fact to increase or decrease rewards going to any particular person or group of people, it is to make Steem work better to stop or reverse the slide into obscurity and ultimately failure. Yes I'm sure there will be some net winners and losers but at this point I'm not even sure who they are.