WordPress introduced a brand-new subscription feature [on 9/10]— from WordPress.com

WordPress Subscriptions appear as a tab in the top menu bar when logged in and browsing around WordPressWordPress.com blogs and as a tab on a user’s WordPress.com homepage. The top menu tab can be used to instantly subscribe to any WordPress.com blog, and when managing your subscriptions, you can also add RSS-enabled blogs from around the web simply by typing the blog or site’s URL in a field. New post notifications are available via e-mail and IM, but they aren’t sent to new subscribers by default.