I think ruang was referring to Kleinberger, who applied the idea directly to web pages, as opposed to scientific journals or economies. He did it only short while before Page and Brin, and they even cited him. As to why he didn't make a search engine, I'm guessing it's because CMU is in Pittsburgh.
Kleinberg, not Kleinberger, and he's a prof at Cornell, not CMU. I'd guess it has less to with geography, and more to do with the fact that Kleinberg is a (brilliant, celebrated) academic who probably wasn't very interested in doing a startup.
