As you said the PageRank is just one of the many features used by the ranking algorithm. I highly doubt that there is any patent issue here (it's "just" an eige

As you said the PageRank is just one of the many features used by the ranking algorithm. I highly doubt that there is any patent issue here (it's "just" an eigenvector computation), and there is a ton of literature and practical evidence that you can build very good web-search ranking technologies without PageRank. It would seem very surprising to me that one can patent a feature used in an algorithm for commercial purpose...