| In the SEO realm there is a lot of attention paid to PageRank as an indicator of a domain's value. Although it is probably one of the most important factors in a domain's worth in the eyes of Google, there are a few points that should be mentioned.
Google assigns each page on the web a weight and when one web page links to another it passes some weight onto the page it is linking to. The higher the PageRank, the more likely Google is to trust it. Google PageRank has eleven values, between 1 and 10. Web pages that don't have any PageRank are often referred to as having N/A PageRank.To begin with, for whose who don't know what PageRank is - it is a metric used by Google to decide how important a domain is based on analysis of hyperlinks. This is true for both external and internal hyperlinks.
So, if a page has 4 PageRank 4 and 3 PageRank 3 links pointing at it, it will probably be give a PageRank of 4. It should be noted, pages that have a lot of low PageRank and PageRank N/A hyperlinks pointing to them can have their PageRank lowered as a result. Probably the most important factor in the distribution of PageRank to a web page is the PageRank of the pages linking to it. PageRank is generally not assigned to a page higher than the pages that link to it. Sheer quantity of links does not help to increase PageRank. The higher the PageRank of web pages linking to a given page, the higher its PageRank is likely to be. A website can have a high PageRank with relatively few links pointing to it if those links are of a high PageRank.
Some people suggest that the text content of the page affects PageRank assignment, but this doesn't seem to be the case. There is no evidence that text affects PageRank other than pages that have been spammed often have their PageRank removed.
When it come to sub-pages, time is a factor in PageRank distribution. When new sites first get assigned PageRank their sub-pages often remain without any PageRank. In general, sub-pages are somewhat slow to get assigned PageRank. Google is generally less trusting of sub-pages unless they belong to a trusted domain. In particular websites with a lot of sub-pages and even more so sites that link to a lot of internal pages (like directories) can struggle to pass their PageRank to internal pages.
The structure of the site has a major role to play in the assignment of PageRank. Google uses what is known as block level analysis to analyses web pages. They use their vast knowledge of the architecture of the web to decide what links on a page are probably the most trustworthy and the pages these links point to are more likely to receive PageRank.
Google can and do manipulate websites' PageRank. This is generally as a penalty for sites that have used unhonest practices. This can often cause all the site's sub-pages to loose their PageRank. It has also been claimed that in the past Google has made mistakes in PageRank distribution.
Lastly, the PageRank of a web page may change even though there has been no change in the links pointing to that page. This is either due to changes in the structure of links between all websites or modifications made by Google.
Sky Alfaro is an SEO consultant with the SEM Labs SEO Agency where she helps small to medium sized companies with search engine marketing training. |
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