As @aggroed mentioned, it seems a some of the powder (with regards to witness voting, and not necessarily content) is owned by Steemit staff. We have no idea how much.
There are however some larger accounts who are voting on content, who don't cast witness votes, and it's these that are probably more interesting. As suggested in the post, I feel this is an attempt to stay in the shadows, and not show you are tied to a Witness. Basically so you can self-vote away.
Cheers for dropping in on a stats post, I know some of these aren't everyone's cup of tea. As you can see by the rewards though, these are what fuel the prizes and delegations to others.
Yes I see that about the stats post... I like looking at the stats, I just never really took the time to follow it... Mainly because it seems like I always had things to do, but I'm trying to find some time as I evaluate things a little deeper! Thanks for the explanation, and again for digging out some interesting nuggets. :)