At a guess it's the revamped version of the old red/green bar thingy, coupled to a simple vote counter that allows site mod types to allocate 'ranks' to users... one site I run for school pupils dubs them suitably silly titles like 'Galactic Hamster Third Class' for example.
Not into voting myself, I turned my red/green one off when I found out how - I generally find out quite directly if somebody dislikes me!