When writing a post, the author can decide to mark it as an Announcement if the content is very important and every employee should read it.
If a post is marked as an Announcement, all employees will receive alerts regardless of whether they are following the blog or author. Alerts are sent on-site, through the browser (push notification) and by email, but employees can choose whether to switch off email or browser alerts.
NOTE: This feature might become useless if a lot of posts are marked as Announcements because people will perceive these notifications as spam – so use this option with caution.