Vsevolod Balashov has taken a PHP PageRank decoder and rewritten it in Ruby. It works and it's fast. Simply, it retrieves the PageRank value for a supplied URL from Google and decodes it back to the PageRank value between 0 and 10. Each page indexed by Google has one of these numbers, and have historically represented how well linked a Web site is and how well it will rank in Google. The usefulness of PageRank has dropped a lot in the past year or two, but it can still be a useful indicator of how significant a Web site is.