You'll say these stats are skewed because this is a blog about Google, so it's normal that the readers are more likely to use Google tools. Last year, I used three buttons that made it easier to subscribe to this blog using Google, Bloglines and Yahoo (now I replaced Yahoo with Netvibes). Here's how many people clicked on the buttons versus the number of subscribers:
|Feed reader||Clicks on the buttons (2006)||Current subscriptions|
So Google's numbers seem really big, while Yahoo's numbers (Yahoo also recently started to report the number of subscribers) are way too small. Bloglines is the only feed reader from these three that shows reasonable numbers. Note that Yahoo reports the number of "active" subscribers in the last 30 days, while Bloglines and Google report the total number of subscribers.
If I were to trust these numbers, I'd say Google's feed readers are extremely popular.
Update: As I said in the comments, most of the subscribers are not from Google Reader, but from Google Personalized Homepage. It would've been nice if Google reported the numbers separately.