Hooperman was twittering about fake PR scams on Flippa recently.. like to hear more about how that works
Not Hooperman but I can probably jump in on that one until he gets over here.
It's really quite easy to fake PR on Google.
You acquire a domain, do a permanent redirect (201?), once Google updates PR publicly you remove the redirect.
Google continues to think (from a toolbar perspective) that the domain is the same so continues to give it the PR of the site that you were redirecting to.
So an example,
I buy www.example.com and redirect it to www.Adobe.com until the Google PR update occurs. Once the update occurs, example.com gets the same PR as adobe.com (9 I believe as I don't have the toolbar installed at work). You then remove the redirect (because you don't want potential buyers going to the site and getting redirected to adobe) but lo and behold, the toolbar still shows a PR of 9 to the unwary.
Now most scammers are smart enough not to fake a 9, but they can easily fake a PR or 5-6 and use that as a selling point.
So how can you spot a fake PR?
Easy, if you know how There are a couple of ways, you can go to Google, type in the url and check the url of the page that is returned, if it's different then the PR is fake. You can also check the cached page (no cached page is suspicious in itself but that's another post) to see if it matches the site (you should do this anyway as part of your due diligence).
There are also fake PR checkers out there such as http://www.checkpagerank.net/ that you can use.
I suppose I was thinking of the more recent development on the "useless green pixel bar" where Google has been grey-barring those translation pages if they are not regularly picking up links from elsewhere.