Dan Bricklin prepared a screencast (7Mb, .swf) as an introduction to using wikiCalc. In it, you will see him paste from Excel and mashup stock quote and charting feeds. The Associated Press posted a in-depth profile of Dan that's a great read. Also read his blog posts working with Socialtext and the Beta release.
UPDATE: Podcast with Eric Lundquist from eWeek and Dan Bricklin.