Yesterday when I opened google, I had a surpriese. There were two icons in the right of each serp: one up arrow and one close icon. So, what was the first thing I thought about ? -- Will google be going collaborative? Will the USER make the google SERPs in the next months? Do you have any information about it ? I'm afraid SEO will be changing totally from now on.
It was there for a while, but that's for your own preference I guess. Google probably won't count it into the ranking or else everyone will try to move their site to the top.
As shulink said, it only affects what YOU see in the results... Not how they rank URLs for the public at large. Using it for ranking purposes would be absolutely foolish because it would be totally spammable. I think they're a little smarter than that.