How can PageRank be faked

I recently came across a useful tool at 321pr.com/ It attempts to determine if the URL that is given has a real or faked PageRank. You might wonder why, in a time where nobody pays any attention to the little green bar, that anyone would need a tool like this. But when analysing the search engine results in order to find out why certain sites are ranking above or below yours, it can be useful to know.

The faked PR is achieved by a dangerous method which can result in a Google ban and at best, will only last a few weeks or months. A 301 redirect is put in place which is only activated when the IP number of the Googlebot is detected. Google assigns the PR to the page with the redirection thinking that both pages are identical. So if your 301 redirects to adobe.com you can pick up a PageRank of 9 or 10. In this case, the 301 redirect only effects the Googlebot, any other visitors will see the usual site with a PR9

How do you detect a faked PageRank?
Use an online tool such as www.321pr.com or search for info:dodgydomain.com (use the domain that you want to check.) If there are no results or if the URLs in the results differ from the original URL then the site's PageRank has most likely been faked.