Internet Explorer

Internet Explorer is Microsoft's first venture into the web browser market. The initial version of the browser was incarnated from Spyglass Mosaic which Microsoft licensed for a modest quarterly fee and a share of the non-Windows product revenues. As Microsoft decided to distribute Internet Explorer "free of charge" with their Windows operating system, they were able to avoid most royalties.

Because of the browser's inclusion starting from the Windows 9x series and beyond, it sparked a [https://en.wikipedia.org/wiki/United%20States%20v.%20Microsoft%20Corp. three-year-long antitrust lawsuit] that lasted until November 2001. The browser quickly overtook Netscape in the first browser war and retained ~95% of its market share until the early 2000s, when popular alternative browsers such as Mozilla Firefox and Google Chrome came to market, sparking the second browser war.

Internet Explorer was notorious for disobeying set web standards by the W3C until version 9, when Microsoft took a new commitment to HTML5 and web standards. It was eventually replaced by Microsoft Edge in 2015.

End-of-life
On 17 August 2020, Microsoft announced that Microsoft 365 apps will no longer support Internet Explorer starting on 30 November 2020 with the Microsoft Teams Web App, followed by all other 365 apps on 17 August 2021.

Microsoft is set to discontinue Internet Explorer on 15 June 2022. As of Windows 10 build 21387, the browser's functionality has been disabled and attempting to open its executable will instead redirect the user to Microsoft Edge, though it is still possible to run Internet Explorer if  is replaced with a copy from older builds.