The blog subscriptions feature of WordPress.com allows readers to signup and receive emails when new blog posts are published on any blog. The subscriber can select how often this email is sent (the delivery frequency – immediate, daily, or weekly), as well as when this email is sent (the delivery window – a specific day and hour).
Note that subscribers do not need to be registered with WordPress.com. Anyone subscribing with an email address not associated with a WordPress.com account will be sent details of how to confirm and manage their subscriptions without needing to register at WordPress.com.