jersey_guy - 9:30 pm on Feb 21, 2011 (gmt 0)
Google has complete and free access to Google Reader, that much is uber obvious. The more subscribers a url has would seem to make your url more "popular" but it is especially relevant when the user has subscribed to it themselves, which is most likely why they are displaying it, to add to their personalized search features. A Google Reader subscription probably is a ranking factor with as much value as a social bookmark has.
GWT also shows Subscriber Stats under Your Site On The Web, but those are for RSS feeds available on site, not from Google Reader.