Based on some of the other comments that are starting to get posted, I think I am starting to understand this. Is it basically that someone with a high amount of SP can designate a certain number of people to 'share' in their Steem Power, so the weight of those people's votes is more than what they would have with their own SP?

But as I pointed out in my longest comment post, this reduces concentration of votes, thus opening a potential vulnerability to those who will (collude to) form voting pacts (coalitions) to game the rewards for their maximum benefit.