URL discovery is one thing; ranking that discovered URL at number 1 without any other signals is another. I don't think anyone cares that much about how Bing do

URL discovery is one thing; ranking that discovered URL at number 1 without any other signals is another. I don't think anyone cares that much about how Bing does URL discovery (unless, of course, the URL is supposed to be private and exchanged via email). Given that they have a new URL, what made them rank it #1?