salam every one, this is a topic from google web master centrale blog: Webmaster level: All
Today we’re making a change to the way we categorize link data in 
Webmaster Tools. As you know, Webmaster Tools lists links pointing to your site in two separate categories: 
links coming from other sites, and 
links from within your site. Today’s update won’t change your total number of links, but will hopefully present your backlinks in a way that more closely aligns with your idea of which links are actually from your site vs. from other sites.
You can manage many different types of sites in Webmaster Tools: a plain domain name (
example.com), a subdomain (
www.example.com or 
cats.example.com), or a domain with a subfolder path (
www.example.com/cats/ or 
www.example.com/users/catlover/). Previously, only links that started with your site’s exact URL would be categorized as internal links: so if you entered 
www.example.com/users/catlover/ as your site, links from 
www.example.com/users/catlover/profile.html would be categorized as internal, but links from 
www.example.com/users/ or 
www.example.com would be categorized as external links. This also meant that if you entered 
www.example.com as your site, links from 
example.com would be considered external because they don’t start with the same URL as your site (they don’t contain 
www).
Most people think of 
example.com and 
www.example.com as the same site these days, so we’re changing it such that now, if you add either 
example.com or 
www.example.com as a site, links from both the www and non-www versions of the domain will be categorized as internal links. We’ve also extended this idea to include other subdomains, since many people who own a domain also own its subdomains—so links from 
cats.example.com or 
pets.example.com will also be categorized as internal links for 
www.example.com.
| Links for www.google.com | External links | Internal links | 
| Previously categorized as... | www.example.com/ www.example.org/stuff.html
 scholar.google.com/
 sketchup.google.com/
 google.com/
 | www.google.com/ www.google.com/stuff.html
 www.google.com/support/webmasters/
 | 
| Now categorized as... | www.example.com/ www.example.org/stuff.html
 | scholar.google.com/ sketchup.google.com/
 google.com/
 www.google.com/
 www.google.com/stuff.html
 www.google.com/support/webmasters/
 | 
If you own a site that’s on a subdomain (such as 
www..matrixar.com) or in a subfolder (
www.google.com/support/webmasters/) and don’t own the root domain, you’ll still only see links from URLs starting with that subdomain or subfolder in your internal links, and all others will be categorized as external links. We’ve made a few backend changes so that these numbers should be even more accurate for you.
Note that, if you own a root domain like 
example.com or 
www.example.com, your number of external links may appear to go down with this change; this is because, as described above, some of the URLs we were previously classifying as external links will have moved into the internal links report. Your total number of links (internal + external) should not be affected by this change.
As always, drop us a comment or join our 
Webmaster Help Forum if you have questions!
Posted by Susan Moskwa, Webmaster Trends Analystthis is a topic published in 2013... to get contents for your blog or your forum, just contact me at: devnasser@gmail.com