From the wikipedia page of Robin Li, co-founder of Baidu: https://en.wikipedia.org/wiki/Robin_Li#RankDex

> In 1996, while at IDD, Li created the Rankdex site-scoring algorithm for search engine page ranking, which was awarded a U.S. patent. It was the first search engine that used hyperlinks to measure the quality of websites it was indexing, predating the very similar algorithm patent filed by Google two years later in 1998.