In this particular example, our server is set up to default (C-name) to the non-www version. The site is 8 years old. In the past, we used to link to it using the
www. For some reason, about 2 years ago, I made the decision to link to it and our other sites without using the www in front. Both versions of the site are identical.
Bill, I think that you're right that google somehow makes a decision to determine which it will list, the www or non-www url of a site whether the site is identical or not (I didn't know that they could not be identical).
In my case, google has been listing the www version for years even though we've been promoting the non-www version. Now, all of a sudden, with no rhyme or reason, I'm seeing the site sometimes listed without the
www. I prefer this because that url has more backlinks and higher page rank.