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.
I do believe that the Internet/WWW is one of our greatest inventions, though, so this is just nit-picking. :)