I may be forward thinking a bit too much, but this +1 is giving me a creepy feeling. Does nobody here click +1's? Has anyone looked at how doing this impacts the SERPS in their browser? It's like herpes? You carry that baggage forward when using Google search? Ah, you can always sign out but which casual user ever does that?
It's quite possible that this is well beyond any personalization. Yeah yeah more personalized results has been around with Google. Yeah they might be using that more and more. However, the big game changer might just be that +1 button that you click.
My gut feeling is that the +1 is helping take the SEO out of Google. If people don't "get it" now, it might sink in soon enough. It appears to me that a +1 click means that you will see less unknown sites and more of that +1 site in your search inquiries that are relevant to that site.
It's odd in a way. You need to get seen to get people to click that +1, yet you can't get those people to click the +1 because they can't find your site in the SERPS.
Google wants a people run search result engine? It's almost here in my mind. SEO that? Good luck.