How can I get a history of a website's PageRank?

Question

I want to view, in any format, how the PageRank for a particular URL or domain name has changed over time. Some tools can provide this information from the first time someone manually submitted a request for that site. I would prefer a solution where monitoring of a site is not triggered by a human-made request.

Answer 1

While not exactly the Google PageRank, Alexa will show traffic history and reach history for a given website.

Answer 2

URL Trends offers this information. Enter the domain you want to look up and hit Site Rankings on the left.