"The demographic site selection option is found on the ‘Identify sites’ page when you create a new site-targeted campaign, or on the site tool in an existing site-targeted campaign. In both cases you’ll also be able to use two other options to find sites: listing site URLs and describing topics that match your ad. We recommend using those methods along with demographic site selection to identify the very best sites for your ad to appear."
Merely US customers can enjoy demographic site selection and yet this is applied to Google AdWords Content only. Meanwhile, Google still has no plan to expand demographic targeting into its search.
On the other hand, MSN is affected very much as previously demographic targeting is one of adCenter main turfs.