No, this is not an early April fools joke. Microsoft announced today that it is going to discontinue its MSN Encarta web sites on October 31, 2009:
"On October 31, 2009, MSN Encarta Web sites worldwide will be discontinued, with the exception of Encarta Japan, which will be discontinued on December 31, 2009. Additionally, Microsoft will cease to sell Microsoft Student and Encarta Premium software products worldwide by June 2009.
Encarta has been a popular product around the world for many years. However, the category of traditional encyclopedias and reference material has changed. People today seek and consume information in considerably different ways than in years past. As part of Microsoft