Google PageRank Associates Primary and Sub Domains

By Scott

Warning: This is a geeky post!

When we launched our blog (that’s what you’re reading right now) we decided to conduct a little experiment. Rather than run it from our main domain directory ( we decided to call the blog from what’s known as a sub domain (

Don’t know what a “sub domain” is? Simply put, the www you see in website addresses is actually called a sub domain ( We set up our blog such that “blog” replaced “www,” which is why the address for our blog is

Our main site ( has a “PageRank” of 5 according to the Google Toolbar. We wanted to see if our blog would automatically have the same PageRank as our main site. In other words, we wanted to see if Google was smart enough to associate with

For the first few months, even though Google listed our blog immediately in their search engine, the Google toolbar did not indicate that Google associated the two sites. We knew this because the “PageRank” was listed at 0 of 10. Here is a screen shot:

Just recently, out of no where, the PageRank listed for jumped from 0 out of 10, to 5 out of 10. Coincidentally, that’s the same PageRank as the main website, even though there are still very few inbound links to our blog and a 5 out of 10 takes a good amount of time to attain. Here is a screen shot of what it looks like now:

Conclusion: This very small and anecdotal experiment shows us that Google is smart enough to connect the page ranks of sub domains within the main domain of a website.