If a browser clicks on a link via the web proxy then it will pass ProxyRank to the page you clicked on. If you hide your link from humans or place a link that isn't relevant then few people will click on it, so it'll pass very little ProxyRank.
Wow, that really is an interesting explanation. Itís to bad Google just doesnít come out and explain it themselves what it is for. Not many public companies can launch something this significant without explaining why they are doing it. You would think people who own stock would have a right to be informed exactly what they hope to accomplish with this thing.
Any how, this makes a lot of sense, and will have a real impact on the whole link swapping exercise going on.