1. WWW and non-www sites are treated as the same site
2. Sub-domains are now treated as internal links

Where Google previously classified sub-domains as an entirely separate site - meaning that a link from a sub-domain was considered an external link within Webmaster Tools, Google has now introduced changes on the Webmasters Tool that will classify links from sub-domains as internal links, not external links.

Confused yet?

Here is an example to help you out:

If this website had been registered as ineedhits.com/example then previously, links from ineedhits.com/example/sample would be classed as internal and those from ineedhits.com would be classed as external links. Now however links from both domains will be considered as internal links.

Until now we knew that example.com and www.example.com were considered the same site, but from now now on example.com or www.example.com will both be considered as different versions of the same domain and will be categorized as internal links. Even links from info.example.com and about.example.com will be categorized as internal links.

All this can be summed up in the form of the following table.

One impact of this reshuffle on website owners will be that root domain owners will see their number of external links go down. Those with a  sub-domain only should not see any changes. What must be remembered is that the total number of links for both owners will not change.

Although the purpose and impact of this change is still not known, webmasters should be on the front foot and analyze any affect this link reshuffling has on your Google ranking.