“First of all, subscriber stats are now available. Webmaster Tools now show feed publishers the number of aggregated subscribers you have from Google services such as Google Reader, iGoogle, and Orkut. We hope this will make it easier to track subscriber statistics across multiple feeds, as well as offer an improvement over parsing through server logs for feed information.” (link)
We’ve found the Webmaster Tools very useful in maintaining our various sites.
Like everyone, We interested in knowing how many readers our sites have. Estimating this is not trivial, unfortunately. Using an analytics service like Sitemeter or Google analytics shows you a lot about visitors who actually visit your site. But if you offer some of your content via feeds, as virtually all blogs do, then of your readers many visit your site infrequently even if they read your content every day. This is especially true if your feed contains the full post content.
So, you need to estimate the number of feed subscribers you have and factor these in to your actual visitors. Doing this is complicated, too, since readers can subscribe in many ways, e.g., directly via a web browser like Firefox or some other software they run on their own computer or through a service like Bloglines, My Yahoo or Google Reader.
If you use Feedburner to proxy your feeds, these get aggregated to some degree. Many of the feed reading services share subscriber statistics with Feedburner, but not in a uniform way. You also might still have subscribers to some direct legacy feeds, as we do for many of our blogs. And, of course, some people, including David Winer, don’t want to use Feedburner because they are worried that it has an unhealthy monopoly.
So, if you obsess about tracking your readership, you may want to sign up for Google’s Webmaster services, register your blogs, and verify your ownership of them. Then you can get direct information on your Google Reader subscribers.