Google’s webmaster tool video dealt with this question in a recent video.
When Google encounters a page without links it judges it by the content and the keywords it finds. The first instance of the keyword indicates the subject matter then several repetitions confirms that page is about that subject matter. However, there comes a point where the repetition is judged as keyword stuffing and a negative effect occurs. If the page is about a very niche topic or phrase then it has the potential to rank better for that non-competitive keyword than a highly searched phrase.
Many SEOs and webmasters have been wondering why their sites PageRank is not changing despite a lot of activity in publishing fresh content and getting quality backlinks.
No PageRank Update Soon
Google will not update PageRank Toolbar any time soon according to Matts Cutts. This has come as no surprise since many in the SEO community have waited for one of the longest periods between PageRank updates the last one being February 2013. It has also been rumoured that Google may do away with Pager rank altogether.
This revelation will make the work of SEO much tougher along with loss of Analytics organic traffic information about keywords used to find your site and removal of the keyword tool that many used to research keywords for page content and link building.
The reason Matt Cutts gives for Google not updating PageRank as often is that it is not easy to install the toolbar on internet explorer and chrome does not have it. He does not mention Firefox and some chrome plugins that support this data.
Content Does Not Affect PageRank
Another eye opener was that Matt Cutts clarified PageRank is not actually about the amount and quality of content on the website directly. PageRank is more about the number and quality of backlinks. If sites linking to you have high PageRank then they will pass that on and improve your PageRank too. However, it is a bit of chicken and egg situation in that if you produce quality content then quality sites may be more willing to link to you.
A good pyramid type site structure is also important in passing PageRank. Ideal structure is where important pages are no more than a couple of clicks away from the homepage.