I'm just trying to answer the question of the thread (unlike you) .. I know what PR means in ranking factors these days .. Please try to make difference between forum and private messaging ..
Its not the number of back links that Google counts but the number of quality of back links that you are getting. Google gives more value on the quality compared to those irrelevant sites that you are getting.
Most do not understand how PR works at all here. Page rank is factored on about 120 different attributes or factors. Let me give you a few examples. To get to a PR4 for "Mexia Texas Real Estate" which is a small town in texas would take no more than a few hundred quality links, but probably not more than 500 good links that are in content, anchored right and has some of the targeted keywords in the title and/or content of the pages that the links are coming from. Now, if you target "Houston Texas Real Estate" it may take 10 k of the same types and quality of links as mentioned above. Basically it is about the competetion. You may need 40k or more quality links to get a pr4 for "weight loss" Revelence, title, placement of links, IP addresses of where the links come from, comp, and many other factors are involved. The title is the most critical part of determining what will be needed, because that is what Google looks at first to determine what the site is about. This is why blogs with just the name as a title of the hyomepage is so easy to build PR on. A title like "The Musings of a Corrupt Tea Plucker" could probably get a PR 6 in 4 to 6 months with little effort because there is no competition for "The Musings of a Corrupt Tea Plucker" . This makes it so that there is no competing sites and therefore easier to build PR with just a few hundred good links that are anchored with at least part of the phrase, and coming from "pages" (notice I did not say sites?) that have 1 or more of the words in the title of the example title and blog.
Hello, my other message was in reply to you. It wasn't aimed to be a nasty response. I just wanted to let the people in the thread know that there is a lot of info on the web that maybe once stood, but now is not true. You then get people in other threads saying stuff like "I have xx number of links, why don't I have this PR that it says here".
my blog reaching PR0 to PR1 very fast just couple of months, an I just maintain on running untill now past 1 year my blog still PR1 without major increasing.
I don't think say getting a link from a pr5 to your site will help that much if there are many other links on the page as well, and if it's dofollow there usually are plenty of others either on the page or find it shortly. Don't expect a page like this to give you much link juice if any at all.
To get a rough measure about how much backlink you need for getting a PR3 site , you can refer this page rank table http://jladevelopment.com/content/estimation-pagerank-table
There's no sure number. You can get a PR 3 with only 50 backlinks but those better be some good links. Or, it can take thousands if most of them aren't quality links.