When one day Microsoft decided to create the multimedia encyclopedia called Encarta. At the time they knew that it would revolutionize the landscape of encyclopedias, becoming the industry leader. But it took until 2005 for the stable version of Microsoft Encarta to be released, and that soon became an indispensable tool for both students and professionals alike. They were even allowed to suggest changes to Microsoft, along with ideas for things to be included in later versions.
Unfortunately, Microsoft decided that the competition from free sites like Wikipedia were damaging their sales, and so decided that the time and effort needed to keep it up to date weren't cost-effective. Thus they stopped selling the Encarta Encyclopedia in 2009. This is despite its tremendous growth, as it had over 62,000 articles, which were supplemented with pictures, maps, audio and video, timelines, interactive activities and atlases. All this, and in several languages too.
Although Microsoft doesn't currently offer any alternative to Encarta, many of us still have hope that someday they'll launch a new version of Encarta.
NOTE: This program doesn't have downloads available. The "download" link in your tab will take you to their website, where you can find more information about Microsoft Encarta.