Google and other search engines, with “spiders”, crawl the web, reading and navigating across links much like a human surfer. In doing so, they create a mapping of the connection between sites to determine sources of trust and authority, and in turn, sites worth ranking.

Link Value

The more links a site has pointing to it, the more value it is said to have. But, it’s not just about quantity; it’s about quality too. Links have value in proportion to the trust and authority of the link source. So, if you want a strong domain from a search engine perspective, you want lots of people linking to you, and you want lots of people linking to the people linking to you.

Pagerank

Pagerank is a term you often hear. It is named after Google founder Larry Page and refers to a currency of link value. A link from a strong site passes more Pagerank than one from a weaker site. A site with many strong links pointing to it is said to be a high Pagerank site.

Pagerank is quantitative and cumulative, but it’s tricky to actually measure. The only real number you get is a number supplied by Google per page. The score given is either n/a, or any number between 0 and 10. The scale is not linear, and more logarithmic instead, such that increasing by one point represents a tenfold increase in value. I’ll be as precise as I can be at the end of the post.

The score, accessed by and given in SEO toolbars, is updated roughly a few times per year, although lately Google has updated pages more often. In general, the pagerank score provided in a toolbar (toolbar Pagerank, or TBPR) is a fairly good approximation of the quality and quantity of links pointing to a site, although it’s not completely reliable indicator.

Spreading the Juice

Think of link value as a liquid that can flow between pages (which is why it’s often called “link juice”). To a certain extent, linking out from a page somewhat reduces that page’s Pagerank, as there is a degree of finitude to the shareable quantity. This is especially the case with internal links, as Pagerank can pass between pages on the same site, too. You will want to see the Pagerank score of not just the homepage, but of subpages, too, and hope for PR spread across the site, especially to the most important pages.

What’s Good?

A good PR score partially depends on the niche, and the types of links that produced it. For example, a PR3 page caused by one PR4 link is not as worthwhile to me as a PR3 page caused by three PR3 links, a few PR2s, 1s, and 0s. Also, there’s a big space between each number, and while you can’t see it defined more precisely by Google, one PR2 site could be a lot stronger than another PR2 site. And add to that the fact rarity of PR updates and you see why this isn’t the perfect indicator. A site that shows n/a could be a 3 at the next update. You have to look at the links.

Regardless, here’s a rough guideline to help you get started a bit. These are descriptions of TBPR scores for a site’s homepage, and how I generally interpret the value of a site before checking the TBPR on subpages and checking all the links coming in:

n/a – Not yet given a score by Google, potentially relatively useless from a Pagerank standpoint. This is tricky because it can represent extremely fresh content, which is increasingly important to Google results. For example, a new blog post will be n/a, but a link from a new post on a popular blog would be great.

0 – A penalized page, or a page with no real link value to speak of. Still, if the site is legit, a link from a PR0 is normal and good for adding variety to your backlink profile. Approximately 0-2 fairly weak links. I wouldn’t buy a site like this in most cases.

1 – A site that has been online a while but without much in the way of links. Maybe just a few, from fairly weak sources (no sources linking in above PR2). In general, I wouldn’t buy a PR1.

2 – A worthwhile PR score, at a decent kind of level. This is a sign of a minimum good standard, and would be a nice link to get. In fairly small niches, PR2 is relatively high. A PR2 score could be the result of one PR3 link, or a few 1s and 2s. If the links were clearly niche-focused and the domain name fits the niche, I would be happy to pay $50-75 for a PR2 domain

3 – I find this is the kind of score that’s given to sites who are clearly authoritative (official band’s website, for example) and when the links don’t necessarily justify the PR. One strong PR4 link can grant a three, but I’d be happier with a few 3s, 2s, 1s, and 0s linking in, to diversify a bit. I would pay $75-150 for a site like this depending on the content and other variables.

4 – A few PR4 sites or one PR5 site will often create a PR4. This is a site that’s in what I consider the lower end of the middle tier. It is a site with recognized authority, and is likely ranking for many of its terms. It depends on the size and competitiveness of the niche, of course, but 4 should bring traffic in most cases. I would pay approximately $100-500 for a good PR4 domain.

5 – Few sites get to a real PR5 without being actually popular sites. Only very strong and old, or very active and link-filled current sites have a chance. At this level in many niches, 5 represents some dominance and high potential, and are often clear hubs within their niche, that everyone tends to link to. A strong PR5 is worth $500-2,500 depending on the other variables.

6 – This is likely a strong and meaty source, likely with 6-figures of links, many of them from very high authority (PR5 and 6 sites). At this level, the site likely has a ton of content, and has been recognized with links from longstanding authority sites in their respective niches. This is the rough boundary of the middle tier. To me, a PR6 is in the $5,000-10,000 range.

7-10 – Sites with this range of PR scores generally fall under the same class. They are all extremely well-known in their niches as primary sources. Sites at this level set the tone for authority. Inbound links are in the millions and billions. They are often well-known brands, and almost invariably high traffic sites. You will likely never get an opportunity to buy a PR7-10 domain. If you can, under $10,000 would be a lovely price.

If you disagree of have more to add to my assessment, please comment below! Until then, when I feel like some geeky fun, I guess the PR of a site by the look of its homepage. You really do start to get a sense of the classification eventually.

Hopefully this clears some things up and helps explain why Pagerank and link value are important to any domainer, and why having a sense of how it works can add useful precision to domain assessment, helping you fetch the best justified price for your domain sales, and helping you find good deals.