netmeg - 4:56 pm on Nov 12, 2010 (gmt 0)
I haven't noticed any changes in ranking or pages indexed. Just the home pages being listed as www. And it's not happening for all the sites I own or oversee. Just some.
Probably should clarify about GWT. First of all, as far as I know, they are only asking you to verify both www and non-www if you tell GWT to set a preference. At least that's the way it is with my hundreds of sites. The only ones I have to verify both ways are the ones where I've gone in and told Google to display my site as either www or non-www (instead of leaving it up to G to figure out)
And having to verify both actually makes sense to me; they're not necessarily verifying that you OWN both, but that you control both. www is pretty much considered a subdomain, and it is entirely possible that two different entities could control two different sites on www and non-www. It may be rare, but it's possible, and by verifying both, G makes sure that when you establish the preference, you're not advertently or inadvertently wiping out another site. I also have to verify my other subdomains, like blog.example.com and store.example.com. www is just another subdomain, really.