Actually, that link is extremely old (in internet time) and has outdated information. The c-index is currently based only on the voting in the voting-booth (random voting).
Alright, then let me ask this..I saw a photo of a bus or train terminal, with absolutely nothing in it of interest, it is dark, dreary, no people, no character...they received a c index of 5 so far...I have seen photos that are amazing photography of landscapes with great lighting, and all the other things that make it good..and it has no c index..I am not only talking of photos that have been on here a while or are in the permanent gallery, but also photos that are fairly new. I just wanted to understand it. I suppose some of it comes from what type of people like what type of postings in the voting booth. I do feel the voting booth is a success, I think over time it is increasingly being used more and a lot is accomplished by it. I just wanted some input on this in hopes of my own understanding.
You can't compare the c-indexes of two images if one of the images doesn't even have a c-index. No c-index just means that there have not been enough votes cast.