Google PR and What is minus one at page rank means?

One of the highest talking chapter for webmasters, bloggers, e-entrepreneurs and marketers is Page rank of website or Blog. 

I am trying to give a little explanation on Google’s Page Rank and -1 page rank valuation. Here summery is included for our readers. 
1. What is PageRank?
PageRank is a value calculated by Google for every url. In the early days of Google it was an important factor for the ranking in the search engine, but nowadays it is only one part of the Google Ranking Algorithm. But for most people it is still a very important criterion for buying a domain. Wikipedia got a very good and more detailed explanation about PageRank.
2. Why is it starting at -1?
Normally the PageRank starts with 0 and ends with 10, but if the domain/url is still unknown to Google (in the sense of PageRank anyways), the PageRank check returns a -1. Other tools indicate this with a gray PageRank bar. After a domain is online for a while, it gets a PageRank of 0 from Google.
3. Why is the PageRank bar sometimes red?
Red PageRanks are faked PageRanks. If you redirect your domain on a high PageRank domain your domain will get the same PageRank after some time, but it is not the real deal. If you remove the redirect your domain will keep the fake PageRank till Google decides to update the visible PageRank again (PageRank Update). To find those Domains faster or even filter them out completely I added the Fake PR Check and the Fake PR Filter.
4. How does the Fake PageRank Check work?
There is a very simple way of checking for Fake PageRanks. You have to Google “”. If the result you get does not show you the domain you requested, the PageRank is faked. If you see the right domain, the PageRank is real. If you don’t get a result, the domain is not known to Google and you can’t validate the PageRank this way. You can just click on the PageRank bar and you will be redirected to the Google info results to check it yourself.
5. What does a orange PageRank mean?
I got a lot of messages telling me the Fake PR Check is not working! Why is the PageRank not red for some domains? The PageRank is clearly FAKE! As the answer before stated I use the Google info result to determine if the PageRank is fake or not. As mentioned Google does not always return a result, so it is not always possible to validate the PageRank. That’s why i added the orange PageRank to mark the Domains i can’t be sure the PageRank is valid or fake. There is a filter for those unsure PR Domains as well.
 – The PageRank is real.
 – The PageRank is fake.
 – The automatic PageRank Check could not validate the PageRank.
6. Are there other ways to validate PageRank?
If you are unsure if the PageRank is real, you can take a look at the Backlinks. A PageRank 5 Domain with 0 Backlinks is most likely not what you want. Because the “stolen” PageRank results from a redirect of the domain, you can check for that. An other good indicator for this is the Alexa Ranking Page. Alexa got the same problem with redirects, but if you look at the Alexa Ranking Page, you see the stats for the real site.
7. Will a Pending Delete Domain or Deleted Domain get its Pagerank back??
The PageRank is calculated from the links pointing to the domain/url. So if the links to the domain will not be removed after you registered the domain and put up a website with content, you should get back the PageRank. There are no grantees for it, but my experiences are that you will get it back (or close to it in some cases) if you put up a website and give it some time. 
Google does not update the visible PageRank that often anymore, so it can take several month between PageRank Updates. I encourage everyone to try it out and make your own experiences with it!
If you want to know more about Google’s page rank then must visit Google Product forum