Webmaster tools "Preferred domain" question?

I found this option in webmaster tools and I'm not sure whether it's good or not to change it. It can either

Don't set a preferred domain
Display URLs as www.xxxxxxx.com
Display URLs as xxxxxxx.com

If you specify your preferred domain as http://www.example.com and we find a link to http://example.com, we'll consider both links the same. Learn more about setting a preferred domain.

----

Is this worth changing? Can it help?

bump. Nobody?

I just had to figure all of this out myself. I'm not sure the implications for SEO purposes but I was getting aggravated that none of my links were showing up in GWT. I interlinked all of my pages pretty well (authority site) but no interlinks were found either.

I had been linking everything, at least my backlinks, to the http://domain and I thought WordPress was doing the same when I linked to content. When I went to study it, WordPress was using all the interlinks with the www on them. So, in GWT none of my interlinks were showing up.

So, I went to GWT and set a preferred domain to be www since that is what all my interlinks are. After setting the preferred domain, all my links, including backlinks, started showing.

So, whether or not it's good for SEO, setting a preferred domain helps with statistical purposes in GWT.

Note: you have to "verify" both versions of the domain in GWT before you can select the preferred domain.

Well, it looks like I can add links now, sweet.