What would people be ranked on? Presumably if you were uncongenial and wrong most of the time, you'd score poorly. But congenial folk who post nonsense might score as high or higher than uncongenial people who are usually correct.
And people often post outside their area of expertise (I know that I rarely post about the knowledge I earn my living from): so a new poster might easily be misled by a someone who has ranked highly because of consistently accurate physics posts, who just happens to post some bit of dubious folk medicine one day.
It sounds like little more than an unhelpful popularity contest, as Neverfly says.

Perhaps people should just learn Internet Survival 101, and appreciate that the moment they connect to the Internet they are submerging themselves in a sea of information of dubious provenance. That's life.

Grant Hutchison