A slide show in eWeek.com by Nicholas Kolakowski which lists 10 Microsoft Apps that have bitten the dust or or are likely to go. Thanks @billschrier for drawing it to my attention.
Encarta is on the list. That little beasty killed the Encyclopaedia Britannica single handed and was hailed as a miracle of multi-media information in its day. What killed it: need you ask: Wikipedia and the web. Launched in 1993, died in June 2009 having gobbled up a number of encyclopaedia in its ever more bloated wake.
Soapbox is going too, launched in 2006 as a YouTube killer it handles less than 2% of video content. But so is Microsoft Money, MSN Groups and, perhaps, that weird music player that noone I have ever met, owns up to having purchased: the Zune.