Automattic has introduced a new subscription feature on WordPress.com.
Subscriptions introduces an easy way to track and read posts across multiple blogs in once place, with a single mouse click.
WordPress Subscriptions appear as a tab in the top menu bar when logged in and browsing WordPress.com blogs and as a tab on a user’s WordPress.com homepage. New blog posts will show up in the order in which they were posted, regardless of the blog they were posted on.
WordPress Subscriptions help page and set up info: http://en.support.wordpress.com/global-subscriptions/
