Microsoft
In 1990, Microsoft introduced its office suite, Microsoft Office. The suite bundled separate productivity applications, such as Microsoft Word and Microsoft Excel. On May 22, Microsoft launched Windows 3.0, featuring streamlined user interface graphics and improved protected mode capability for the Intel 386 processor. Both Office and Windows became dominant in their respective areas.
Microsoft Outlook
Microsoft Entourage was introduced as an Outlook-like application for Mac OS in Office 2001, but it lacked Exchange connectivity. Partial support for Exchange server became available natively in Mac OS X with Entourage 2004 Service Pack 2. Entourage is not directly equivalent to Outlook in terms of design or operation; rather, it is a distinct application which has several overlapping features including Exchange client capabilities. Somewhat improved Exchange support was added in Entourage 2008 Web Services Edition.
Entourage was replaced by Outlook for Mac 2011, which features greater compatibility and parity with Outlook for Windows than Entourage offered. It is the first native version of Outlook for macOS.