Outlook Express is an updated version of Outlook that allows users to organize email accounts, centralize business information, and improve customer service. Some key features of Outlook include email, calendar, address book, notes, reminders, tasks, and journal. The email feature allows users to set reminders, send messages to multiple people privately, and sort messages. The calendar allows adding holidays, viewing multiple days, and sharing with customers. The address book integrates with email and calendar to quickly contact and schedule meetings with contacts.