Check the post link below for an overview of Google Related
Old is New Again: A Bit of Contextual Search History
For the web search historians out there, here are a few of the context search products we’re talking about. Most were around in the the late 1990s or early 2000s.
Google Related was developed by Google’s R&D Center in Israel. The person in charge at the center is Yosi Matias who was the Chairman, CEO, Co-Founder of Zapper, a company that was doing contextual search in the late 1990s. Here’s a paper on contextual search by Mattias and his colleagues at Zapper: Placing Search in Context: The Concept Revisited. The paper was presented at WWW10 in 2001.