search mysite.com and www.mysite.com

differnce "mysite.com" and "www.mysite.com"

[vagelis_t]

Hi all,
My site was hit by Google change in 2 February.
Our PR is same (PR 6 ) but when searching for unique pages in my site, that have always ranked at the top, they are now buried.
My Google search traffic is down 70% since the 2 February

When I search into Google's search box "www.mysite.com" returns:

My home page Site title
Site Description

Google can show you the following information for this URL:
Show Google's cache of www.mysite.com
Find web pages that are similar to www.mysite.com
Find web pages that link to www.mysite.com
Find web pages that contain the term " www.mysite.com "

When I search "mysite.com" returns:
3880 results, include my homepage and some other pages contain the term mysite.com

What happens?

Much thanks in advance!