That site is good for listing a character's appearances every now and then, but not much else. It's even more of a mindless popularity contest than Marvel's new user-edited ratings on their official site.
I think it's mostly due to a lack of hits. And not everyone that does it is likely a complete fanboy.
But mainly I just ignore the rankings. It's a decent site occasionally for bios and appearances, like I said, but any coherent comic fan can browse through the list and see the glaring inaccuracies, which basically invalidates all of it.
And sometimes there's misleading questions. Say it's between Raven and Superman: they'll have questions like "Who wins if they only use their magic?" Or "emotion manipulation." You have to answer Raven, even though Kal is >> Raven normally.
To be fair, at the end is a "What if they use all their powers" question, but the intermediate questions that favor one or the other probably skew the results a bunch.