Do the google page rank numbers mean anything in particular? I have a PR4 site, what makes it better than a PR3 but not as good as a PR5?
Its lilke rank position...or likeness remember teh old school days.. there is a 1st position than second( better than three but not as good as 1st ) then third Just reverse the ranking criteria,, here more down u go means 10 is the best and in school 1 is the best Basically it shows the level of the importance google gives to your website
heres what google define PageRank: "Pages that we believe are important pages receive a higher PageRank and are more likely to appear at the top of the search results." http://www.google.com/corporate/tech.html
if you mean it does impact on Your SERP Then its not , PR haven't any importance For SE ranking at all
pr is the number of incoming links from other site. every link doesn't hav the same importance. a link from high pr site has higher value in determining pr. this criteria is also considered in determing in SERP. but it is just one of the many factors there.
If you don't understand what Page Rank really is then I would suggest reading The Anatomy of a Large-Scale Hypertextual Web Search Engine and paying special attention to Section 2. This was Sergey Brin and Larry Page's blueprint for what was to become Google, and a description of what Page Rank is/would become. There is a decent summary of Page Rank on Wikipedia as well. Also, read Google's US Patent on Page Rank. Basically, PR is the measure of your URL's link popularity. It's based on how many inbound links the URL has (both from internal pages and other sites - NOT just inbound links external sites as others have stated) and how strong those links are. To calculate a URL's PR, Google looks at all of its inbound links. For each inbound link they look at the 'real' PR of the page that is linking to you. They divide the PR of that page that is linking to your URL by the number of followed outbound links on that page, and that is approximately how much PR the page is passing your URL when it links to you. I say approximately because there is a damping factor in the equation that causes the PR to decay as you link from URL to URL to URL. They do this for each inbound link to your URL and sum up all of the PR amounts being passed in. That is the 'real' PR that is assigned to your URL. There are 2 types of 'Page Rank'.... The one that is most commonly referred to is the one you can see in the Google Toobar (TBPR). This is the little hopefully green (or gray) bar - a 1 to 10 scaling based on what the page's 'real' Page Rank was sometime in the not so distant past (typically no more than 3-4 months ago). Google updates the TBPR about every 3-4 months... Note: by the time they issue the update, it is already out of date usually by a couple weeks or so. There is also the 'real' Page Rank for a page. This Page Rank is actually what is used by the ranking algorithm. It is updated constantly as Google crawls the web discovering new links to your page and old links which have been dropped. It is said that the mapping from your 'real' Page Rank to your toolbar page rank is based on some logrithmic scale. Your TBPR is a snapshot of the 'real' page rank from some point in the past that is scaled into and shows as the TBPR. So, for example, if the mapping from 'real' Page Rank to TBPR were a based on a base 10 type logrithmic scale then the Toolbar Page Rank might be calculated as follows: Real Page Rank | TBPR 1-10-----------------1 11-100---------------2 101-1000-------------3 1001-10000-----------4 10001-100000---------5 etc. up to-----------10 As you can see it gets exponentially harder to get to the next TBPR. 3 or 4 times per year Google maps all of the 'real' PRs for every URL in their index to an equivalent 1-10 TBPR, and issues an update. As I mentioned by the time the TBPR is issued it's already out of date since it's likely already weeks old. As others have said, your URL's PR is only a very minor factor in how that URL ranks at Google for a particular keyword. It's only one of 200+ ranking factors that they are looking at when they rank your page for a particular keyword phrase. Their are many more factors that carry much more weight... like the link text used to link to your URL. Don't get to hung up on PR. It's better (at least for Google rankings) to have links from relevant pages with the keywords you are targeting as the link text or anchor text for the link than it is to simply have a lot of links or links from irrelevant high PR sites with link text like "click here".
Google has arbitrary algorithm that is proprietary, personally I find my decisions are better than Google's, I even removed google toolbar from my computer and I decide on page worth by myself.