Microsoft Outlook is a personal information manager from Microsoft, available as a part of the Microsoft Office suite. Although often used mainly as an email application, it also includes a calendar, task manager, contact manager, note taking, journal, and web browsing. It can be used as a stand-alone application, or can work with Microsoft Exchange Server and Microsoft SharePoint Server for multiple users in an organization, such as shared mailboxes and calendars, Exchange public folders, SharePoint lists, and meeting schedules. Microsoft has also released mobile applications for most mobile platforms, including iOS and Android.
iCalendar is a personal calendar application made by Apple Inc. that runs on both the OS X desktop operating system and iOS mobile operating system. It offers online cloud backup of calendars using Apple's iCloud service, or can synchronise with other calendar services, including Google Calendar and Microsoft Exchange Server. It tracks events and appointments, allows multiple calendar views (such as calendars for "home", "work", and other calendars you create) to quickly identify conflicts and free time. Users can subscribe to other calendars so they can keep up with friends and colleagues, and other things such as athletic schedules and television programs.