Things that came before Google PageRank

Things that came before Google PageRank:

Social Sciences Citation Index, 1988. Academic database that analyzes citations to see which articles get referred to the most. Those articles are the authorities on a topic.

IBM CLEVER Project- The HITS Algorithm that identified “hubs” that point to “authorities” and was used to calculate the importance of a document. If you get pointed to the most, you’re an authority.