The algorithm for Google PageRank is based on the concept of citations from academia
Quoting from the original paper: "It is obvious to try to apply standard citation analysis techniques to the web's hypertextual citation structure. One can simply think of every link as being like an academic citation. So, a major page like http: www.yahoo.com will have tens of housands of backlinks or citations pointing to it" [L Page, S Brin, R Motwani, T Winograd. The pagerank citation ranking: Bringing order to the web ].
the software was originally meant only to index academic papers
That's not right. From the same original paper:
"PageRank is a global ranking of all web pages, regardless of their content, based solely on their location in the Web's graph structure "
Anyway you are right, and the article's idea sounds way too old: probably an example of two research communities (physics & citation analysis) not knowing too much of each other