Does PageRank only depend on number of inbound links?
The first thing that you need to keep in mind is that there are two PageRanks.
The nominal one, which is the one that shows on your Google toolbar, and which gets updated once every three months or so, and the real one, which gets updated constantly and is used inside Googles search algorithm.
The first one is used just to provide an indication for webmasters, while the second will have a direct influence on your search rankings.
The answer is no.
The number of backlinks certainly plays a role, but Google also evaluates carefully the quality and relevancy of those links.
By quality I mean the overall trust that the site that linked to you has. A link from the Stanford university would have more quality than one from your sister’s blog. Another way to call quality is authority.
By relevancy I mean the proximity of the content on the website that is linking to you, to your own content.
If you have a blog about cats, a link from your sister’s blog that talks exclusively about cats too would be more relevant than a link from the Quantum Physics department of the Stanford university (unless they were talking about Schrödinger’s Cat, but that is a joke only physics lovers will get…).
Let’s consider a example to understand this better. Suppose you just launched two blogs, A and B. Both blogs talk about technology.
On the first blog you decide to purchase 30 backlinks from very small and unrelated sites (most of which don’t even have PageRank to begin with).
On the second blog, on the other hand, you just publish one quality article, and that article gets linked from the homepage of TechCrunch.
If you wait three months and don’t change anything else on the blogs, it is very likely that the the first one would end up with no PageRank at all, while the second one would probably end up with a PR1.
Some other interesting facts about PageRank:
- many people think that PageRank uses a logarithic scale, meaning that increasing your PR gets tougher as you go (i.e. moving from PR5 to PR6 is more difficult than moving from PR2 to PR3)
- real PageRank is not counted from 0 to 10, this is just a scale used for the nominal one
- PageRank is only one of the factors used in Google’s search algorithm, so a high PR does not equate to high search rankings automatically
- Your internal and external links can affect your PageRank
- Content and update frequency have no impact on PageRank