Compared to the invention of the Internet and/or the WWW, I'm of the opinion that calling Google (the search engine) or PageRank (the algorithm) one of the Great Inventions in Human History (and capitalizing it) is too far-fetched. The first is an indexer for the former, and the latter is not so different from eigenvector centrality, with the added spice of directed random walks.
I do believe that the Internet/WWW is one of our greatest inventions, though, so this is just nit-picking. :)
"the latter is not so different from eigenvector centrality, with the added spice of directed random walk" - I think the parent's point was the impact not that the algorithm itself is unprecedented. You could argue in the same way that the wheel is just a solid symmetric disk connected to a hub in the center that helps vehicles move around on a sufficiently even surface. Note that I don't imply that PageRank is as significant an invention as the wheel.
Well yes. That was one of the Great Inventions in Human History.
(Obviously not just page rank but also everything else that made it a working product, but that was the key innovation.)