Page Rank
Page Rank, originally spelled PageRank by Google and still registered to them as a trademark, is now a term more universally used by all search engines, albeit spelled as 2 words. Page Rank is an algorithm used by search engines to assign numerical weightings to web pages, in an attempt to rank or measure their relevance to the keyword or keyword phrase entered to initiate the search.
According to Wikipedia, PageRank is protected by U.S. Patent 6,285,999. It appears, again according to Wikipedia, that the patent is held by Stanford University, not Google, and that the university granted Google exclusive license rights to the patent in return for 1.8 million shares of Google. The shares were sold in 2005 for $336 million. Seems they should have held onto their shares a little longer, not so?
