| 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 aspects of a domain's value in the eyes of Google, there are a few details that should be understood.
Google PageRank has eleven scores, between 1 and 10. First of all, for whose who don't know what PageRank is - it is a value used by Google to determine how important a domain is based on analysis of hyperlinks. Google assigns each page on the web a score and when one page links to another it passes some weight onto the page it is linking to. This is true for both external and internal links. The higher the PageRank, the more likely Google is to trust it. Web pages that don't have any PageRank are often notes as having N/A PageRank.
The sheer quantity of links does not help to increase PageRank. PageRank is generally not assigned to a web page higher than the pages that link to it. The higher the PageRank of web pages linking to a given page, the higher its PageRank is likely to be. So, if a web page has 4 PageRank 4 and 3 PageRank 3 links pointing at it, it will probably be assigned a PageRank of 4. A website can have a high PageRank with relatively few links pointing to it if those links are of a high PageRank.The most important factor in the assignment of PageRank to a web page is the PageRank of the pages linking to it. In addition, web pages that have a lot of low PageRank and PageRank N/A links pointing to them can have their PageRank lowered as a result.
Some suggest that the text content of a page affects PageRank assignment, but this doesn't seem to be the case. There is no substantiated evidence that text affects PageRank other than pages that have been spammed often have their PageRank removed.
When it come to sub-pages, the time Google has known about them is a factor in PageRank assignment. When new sites first get given PageRank their sub-pages often remain without any PageRank. In general, sub-pages are somewhat slow to get give PageRank. Google is generally less trusting of sub-pages unless they belong to a trusted domain. In particular sites 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 architecture of the site has a major role to play in the assignment of PageRank. Google uses what is known as block level analysis to pick apart web pages. They use their vast knowledge of the structure 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 modify websites' PageRank. This is generally as a penalty for sites that have used unhonest methods. 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 updates.
Finally, the PageRank of a web page may change even though there has been no change in the hyperlinks 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. |