Interesting to know who they have invited. Also be interesting to see how the commercial opportunities that will be a reality will effect the topics. I can see a big bun fight coming on between everybody in their respected fields. No one wants to miss out and everyone will want to be considered the authority on the topic. Many "related" articles from one page on a topic to another may contradict the other or even try to discredit the other authors point of view, so in effect, it just becomes like a mini internet (info only) within a search engine/ Web site (Google)
Oh yeah, Knol project looks really good but similar to a paid wiki idea. Well, it is basically a paid wiki idea such as these: http://QuarterWiki.com http://OneBuckWiki.com http://MillionDollarWiki.com
How is it a paid wiki? Google isn't paying the writers to write the content, but they'll earn money via adsense.
I think it's same thing except you don't have to "pay" for your pages. But same concept with one author and revenue coming in from your pages.