What is Google Toolbar PageRank?
The Google Toolbar’s feature displays a website’s PageRank between number 0 and 10. Google has not disclosed the precise method for determining a Toolbar PageRank value.
Google representatives, such as engineer Matt Cutts, have publicly indicated that the Toolbar PageRank is republished about once every three months, indicating that the Toolbar PageRank values are generally unreliable measurements of actual PageRank value for most periods of the year.
The name PageRank is a trademark of Google. The PageRank process has been patented (U.S. Patent 6,285,999 ). The patent is assigned to Stanford University and not to Google. Google has exclusive license rights on the patent from Stanford University. The university received 1.8M shares in exchange for the patent. The shares were sold in 2005 for $336M.