As I understand it, the users can make money there
I have registered but are pretty green yet. I have however understood how it differ from wikipedia:
*You got payed (by ads ?)
*No one can edit your article
*No wikiformat
Have anyone registered and got any money for their articles yet?
Early days, I believe it’s still beta. As for payment, yes, it’s from advertising and the revenues are shared among contributors. (At least that’s according to the official blog, which is cited here.
I’m sooo tempted to write a knol on the JFK assassination, just for the pleasure of titling it The Grassy Knol. 
It seems to me that if contributors are getting paid, and third parties can’t edit the articles, there had better be a very good vetting process to approve an author before letting em write any articles.
As I understand it there won’t be any prerequisites and they want to handle that with user ratings and presumably a bit of search engine magic.
A model that can work with creative stories and essays, opinion pieces and artworks, but I think is problematic with factual articles.
How does knol differ from any of the other ad-supported paid-to-write sites such as triond?
Is it just me or is ‘knol’ a poorly selected not-very-nice sounding name? It sounds really silly to me, but then ‘knol’ means tuber or turnip in Dutch, and can also be taken to mean something like ‘ragged old run-down horse’. And ‘hole in a sock’…
Ouch, the difference in quality is so marked as to be palpable.
Going from the information given in this thread and the Wikipedia page on Knol, my guess would be that Knol will focus more on theses than encyclopedic entries. In which case the formatting and presentation isn’t as important. They’ll also likely have multiple entries on the same or closely linked topics.
Assuming that to be true, I could see how Knol could be considered to not be a competitor with Wikipedia. Really it’s more a replacement for Google Scholar, since the current version almost always leads to nothing more than an abstract.